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THE 



MANUFACTURE OF STEEL: 



CONTAINING 



THE PRACTICE AND PRINCIPLES 



WORKING AND MAKING STEEL. 



A HAND-BOOK 



tor 



BLACKSMITHS AND WORKERS IN STEEL AND IRON, WAGON-MAKERS, 

DIE-SINKERS, CUTLERS, AND MANUFACTURERS OF FILES 

AND HARDWARE, OF STEEL AND IRON, AND 

FOR MEN OF SCIENCE AND ART. 



BY / 

FREDERICK ^OVERMAN, 

MINING EN6INEER ; AUTHOR OF THE " MANUFACTURE OF IRON," ETC. 



PHILADELPHIA: 

A. HART, late CAREY & HART. 

1851. 






Entered, according to the Act of Congress, in the year 1851, by 

A. HART, 

in the Clerk's Office of the District Court of the United States, for 

the Eastern District of Pennsylvania. 



J. FAGAN, STEREOTYPER. 



T. K. AND P. G. COLLINS, PRINTERS. 




(2) 



6-737/0 



to 



it-i 



TABLE OF CONTENTS. 



CHAPTER I. 

Forging Page 13 

Degrees of Heat 13 

Overheating 14 

Forge-fire „ 15 

Tuyere, or tue-iron j water and hot-air tuyere ; rotary tuyere, 16 

Form of its Aperture 17 

Forge for Hard Coal 19 

General dimensions 20 

Portable Forges 21 

Anvil ; making of an anvil ; cast-iron anvils ; block 22 

Tongs: flat-bit tongs; pincer-tongs ; nail-tongs; crook-bit tongs, 26 

Chisels, punches, swages, set-hammer 27 

Hammers, forms of; sledges 27 

Fuel for forging steel 30 

Flux, principles of; sand, borax, borax-glass, borax and sal- 
ammonia, borax and potash 31 

Welding: steel to iron; natural steel; by split joint; shear- 
steel ; cast-steel ; to steel an axe ; shovel ; butt joint ; to 
steel a hammer ; wire draw-plates : chisels ; scarf joint, 35 

Blistered steel, value of 40 

Shear-steel 42 

(no 



IV CONTENTS. 

Cast-steel 42 

Welding steel to steel ; cast-steel ; wootz, 43 

Test of the quality of steel 46 

Hardening of steel; degree of heat; characteristics of hard- 
ened steel; not peculiar to steel; of wrought and cast- 
iron ; difference between hardened iron and steel 46 

Test of hardened steel 50 

Expansion of steel in hardening 51 

Refrigerating fluids ; manner of cooling 52 

Hardening of files 54 

" of needles and cutlery 55 

Making of steel dies ; their breakage in hardening 56 

Hardening by compression 61 

Annealing 62 

Tempering — of small tools ; common tools ; knife-blades ; nee- 
dles ; saw-blades; colours of tempering; in metal com- 
positions 62 

Damascus steel ; imitation of; gun-barrels ; blades 66 

Case-hardening — by charcoal, salt and charcoal, prussiate of 
potash, prussiate of potash and camphor, prussiate of 

potash and borax ; description of iron to be used 67 



CHAPTER II. 

Varieties or Steel 71 

Wootz — description of ore from which it is made ; furnace 
and blast ; manner of its manufacture ; philosophy of the 
process 72 

Damascus steel ; value of scimitars ; imitation of it by 
wrought-iron and lampblack; wrought and cast-iron; 
alloys, alumina and steel ; etching the veins 75 



CONTENTS. 



CHAPTER III. 

German Steel — Natural Steel; what it is made of; steel- 
ore ; sparry ore ; form of forge-fire for making steel. ... 81 

Blast ; common bellows ; cylinder blast ; fan blast 84 

Tilt or force-hammer ; construction of; speed 85 

Faces of hammer ; anvil block 88 

Pillars, or housings ; moving power ; cam-ring ; shaft ; irre- 
gularities in speed ; waste of power; weight of wheel 

and shaft ; number of wipers 89 

Making natural steel ; first appearance of steel in the forge j 
effect of boiling on the iron ; making steel of white or 

No. 2 pig-iron 95 

Use of fluxes , 99 

Making steel from No. 3 pig-iron 100 

Requisites for making steel 101 

Form and dimensions of hearth; quality of bottom stone . . 103 

Practical manipulation 105 

Form of a steel cake ; forging of the steel 110 

Expense of the process 112 

German method of making steel 113 

Making steel in a puddling furnace 115 

Refining of steel 115 

The refining fires ; fuel 117 



CEAPTER IV. 

American and English Method of making Steel 120 

Blistered steel ; amount of steel annually manufactured in 

England ; construction of the converting furnace 120 

Chests, or Cementing Boxes 124 

Charging of the Boxes 1 25 

Cement 126 

1* 



VI CONTENTS. 

Working of a converting furnace 127 

Degree of cementation} trial rods; melting of iron in the 

box 128 

Gain in weight 129 

Tilting 130 

Refining fires ; blast ; operation of welding common steel ; 

shear-steel 130 

Tilts ; form of hammers and tilt-houses ; anvils and hammer- 
heads 133 

Cast-steel 135 

Making of crucibles in Sheffield ; mould for that purpose ; 

weight of a crucible ; mode of drying 136 

Cast-house ; furnaces ; fuel ; time of melting ; manipulation ; 

flux ; tongs ; casting 139 

The mould ; quality of cast-steel 144 

American steel 147 



CHAPTER V. 

General Remarks on making Steel 147 

Wootz 147 

German or natural steel ; difficulty in making it 148 

First element; ore which is qualified; crude iron for .steel; 

leading principles in carrying on a blast-furnace for 

crude steel-iron 149 

Blistered steel; spring-steel in Pittsburgh; saw-blades of 

Philadelphia 153 

Good iron for conversion ; trial by experiment ; by chemical 

analysis 155 

Making the iron for conversion 157 

Cement 160 

Dimensions and material of the converting chests; varieties 

of slabs ; management of the chest 165 



CONTENTS. VU 

A new bos, how dried 167 

Form of iron 167 

Firing of the furnace ; trial-bars 170 

Closing the heat ; size and form of the blisters 172 

Tilting of steel 173 

Cast-steel ; making it directly from iron and lampblack ; 
oxide of iron with cast-iron, or lampblack ; melting of 

wrought-iron ; alloys of iron 173 

Alloys of steel , * 176 

Selection of converted bars , 176 

Form of air-furnaces 178 

Melting pots * 179 

Flux 180 

Tilting of steel 183 



CHAPTER YI. 

Nature op Steel '. 183 

Hardness 183 

Fine cast-steel ; shear-steel ; spring-steel 183 

German steel ; effect of too high or too low heat 184 

Refrigeration of steel ; mediums ; in mercury, in acidulated 

water, in solutions of salt, in oil and fat, in sand, cold 

metal, and air ; manner in which it is performed 186 

Tempering; shades of tempering; manner in which it 

should be performed 188 

Characteristics of steel ; hardness and tenacity ; colour and 

lustre 191 

Texture 1Q4 

Sound , 195 

Cohesion 195 

Elasticity 196 

Specific gravity 197 



Vlll CONTENTS. 

Fusibility 197 

Welding properties . - .+ 198 

Magnetic qualities 199 



APPENDIX. 

Hardness of alloys 205 

Tenacity, malleability and ductility of metals 206 



PREFACE. 

The manufacture of steel is unnecessarily 
shrouded in mystery, which has been the 
cause of its being not more generally in ap- 
plication than it is at the present time. Steel 
is a superior metal for most purposes where 
metals are used, and its manufacture cannot 
be too much cultivated. A principal obstacle 
to its more general introduction is its high 
price ; to effect a reduction in which, has been 
the aim of the author of this work. 

We compare favourably in most branches 
of manufacture, and indeed eclipse other 
nations, except in the manufacture of steel. 
Yet we have materials in abundance, and of 
excellent quality for the purpose ; and it 
needs but proper application to ensure 
success. 

Cix) 



X PREFACE. 

There is nothing particularly novel in this 
book, nor any new inventions recorded there- 
in. I considered it sufficient for all practical 
purposes to record and explain what has been 
done, and confine the illustrations to such 
approved methods as are sure to succeed, 
assuming that improvements upon the known 
mode of manufacture are readily suggested to 
the minds of those who engage in it. 

All I have endeavoured to accomplish has 
been, to develope the science of manufactur- 
ing steel, and explain the philosophy of the 
practical operations. All the facts recorded 
are with this view, as I am satisfied that, if 
our manufacturers understood the philosophy 
of the operation, there is no doubt they would 
soon accomplish much more than the best 
practical operator can perform without that 
knowledge. 

A portion of the volume is devoted to the 
working of steel in the smith's forge, partly 
for the purpose of illustrating the principles 
involved, but chiefly to afford a safe guide to 



PREFACE. XI 

the blacksmith, who is always under the 
necessity of working more or less of this 
material. 

In conclusion, I need only say that my aim 
has been to be of use, and to contribute my 
mite to the general prosperity of the country. 

Philadelphia, March 14, 1851. 



MANUFACTURE OF STEEL. 



CHAPTER I. 

FORGING. 

Degrees of heat. — In this chapter, we shall speak 
of the various degrees of heat required in the manu- 
facture of steel. They are termed, by the black- 
smith, the black heat ; the red, or cherry-red heat ; 
the bright red, or bright cherry-red ; the white, and 
the welding heat. The first-named is the lowest 
heat ; it is not visible in daylight, but shines in the 
dark with a brown colour. The second is, in day- 
light, a blood-red crimson. The third, a yellowish 
red, gives the scales, or hammer-slag on the iron, a 
black appearance. A white heat is that at which 
the scales and iron appear to be of the same colour; 
and the highest, or welding heat, is used for welding 
iron. The latter heat is very variable; for pure, 
fibrous iron sustains almost any degree of heat, so 
long as it is protected by a slag; while cold-short, 
2 (13) ^ 



14 MANUFACTURE OF STEEL. 

or impure iron, bears but a comparatively low heat 
without being melted or burnt. That iron is — and 
for good reasons — considered the best, which bears 
the highest heat : the value or quality of iron vary- 
ing according to the degree of heat it will sustain 
without injury. 

Steel does not bear the same degree of heat as 
iron without injury. The finest cast-steel will hardly 
sustain a bright red heat without falling to pieces ; 
rendering it imprudent to heat it higher than a mid- 
dling, or cherry-red heat. Blistered steel will resist 
a far higher degree of heat than cast-steel; and good 
shear-steel will endure a white heat without much 
injury. Natural and German steel can be heated to 
the welding heat of good iron. 

Although very sensitive to heat, steel will bear 
much more forging than iron, if not previously in- 
jured by too great a heat. In forging steel, no 
heavy tools, or at least no heavy sledge, should be 
used ; a good-sized hand-hammer, with a rapid suc- 
cession of strokes, will be sufficient. This is, in fact, 
the best method of forging steel. 

Overheating, either of iron or steel, is injurious, 
and should by all means be avoided; the lowest heat 
necessary for the work in hand, is the most advan- 
tageous. Steel or iron w T hich has been overheated 



FORGING. 



15 



may sometimes be restored to utility, in a measure, 
by forging, or drawing. This, in the case of iron, 
often accomplishes the purpose intended; it will, 
however, improve burnt steel but little. If, there- 
fore, iron requires care in heating, it is evident that 
steel requires much more. 

Forge-fire. — The means employed for heating 
steel are the same as those used by the blacksmith 
for forging iron. The principles according to which 
a forge for heating steel is to be built, are those of 
fast work and a quick fire. In Fig. 1, a common 




blacksmith's forge is represented. The leather bel- 
lows are driven by hand, or, as here shown, by the 
foot and treadle. The bellows are double ; that is, 
the whole is divided by a horizontal partition, which 
separates it into a working or under part, and a re- 



16 MANUFACTURE OF STEEL. 

gulating or upper part. By lowering the under part, 
after having been raised, the valve in its bottom will 
be forced open by the pressure of the atmosphere, 
and the lower compartment will fill with air. On 
raising the bottom, the lower valve closes, and the 
air in the under part is compressed and forced 
through the valve in the partition, whence the weight 
of the top drives it through the tuyere, or nozzle. 
The pressure may be increased by putting weights 
upon the top. The bellows may be driven by ma- 
chinery or power, where such can be procured, quite 
as well as by hand; but it is better, in such cases, to 
employ the fan-blast, as represented in Figs. 15 and 
16. If the fan-blast can be obtained, it is prefera- 
ble to the common bellows, as it is more uniform, 
and saves fuel ; besides, its use improves the quality 
of the steel and iron. 

The tuyere, or tue iron, is usually a simple block 
of cast-iron, as represented, of six or eight inches 
long and three inches square, with a tapered bore of 
one inch at the smaller, and three inches at the wider 
end. The narrow part, which is directed into the 
fire, can be made narrower by placing an iron ring, 
of more or less thickness, within the aperture. Tuy- 
eres have been contrived of various forms ; but pro- 
bably none will be found superior to that above 



FORGING. 17 

described. Hot-air tuyeres have been used, but are 
now generally abandoned. The water tuyere (Fig. 4) 
is, on account of its durability, very valuable ; but it 
has the disadvantage of keeping the fire cold, which 
is injurious to both iron and steel, but particularly 
to the latter. Another tuyere, now coming very 
much into use, is the "rotary blacksmith's tuyere.' 9 
This appears to be a very desirable addition to the 
forge, as it affords the facility of increasing the size 
of the aperture, and consequently the strength of 
the blast, at any moment, even while at work. Of 
this tuyere, (represented in Fig. 2,) E. Harris, of 
Springfield, Mass., is the patentee. The apertures 
are in a rotary, oblong ball, A, and 
are of various sizes ; so that a larger 
or smaller one may be used by merely 
turning the ball. The whole is con- 
tained in a cast-iron box, closed on 
all sides. The great advantage of this tuyere con- 
sists in the fact that a small fire may be converted 
into a large one, or vice versa, by merely turning the 
hollow ball by means of an axle, which projects at 
one side of the box. 

The form of the aperture of a tuyere is of consi- 
derable importance in the working of the fire. An 

almost cylindrical aperture, such as is represented 

2* 




18 



MANUFACTURE OF STEEL. 



Fig. 3. 




in Fig. 3, throws the blast in a compact, close, and 
almost cylindrical current, into 
the fire ; and furnishes the kind 
of blast required for welding, 
soldering, and small work, where 
the heat is to be concentrated 
upon a particular point. By 
the use of this tuyere, a great saving in fuel is ef- 
fected. To make a cylindrical blast, the cylindrical 
part of the aperture should be at least as long as the 
diameter of the same is wide. 

A tuyere of the form shown in Fig. 4 throws the 
blast over a large portion of the 
fire ; it is useful for heating, but 
unsuitable for welding iron. The 
nozzle from the bellows, or the 
blast-pipe, is in all cases fitted 
closely into the tuyere, and sur- 
rounded by clay, or some other matter. A tuyere 
of the description shown in Fig. 3 makes a small, but 
intense heat ; while one of the kind represented in 
Fig. 4 makes a larger fire, but lower heat. 



Fig. 4. 




:; lt 



FORGING. 



19 



FORGE FOR HARD COAL. 

In working hard, or anthracite coal, no horizontal 
tuyere, nor any of the description above referred to, 
can be used to advantage. A small grate is laid 
in the bottom of the fire-hearth, space being left 
below it for the reception of ashes and clinkers ; the 
blast is then introduced under the grate. Such an 
arrangement may be made at any common forge-fire ; 
but a more perfect forge is represented in JFig. 5. 
This is a brick hearth, about Fig 5 

thirty inches high and three 
feet square, in the centre 
pf which is a square pit, 
into which the blast-pipe is 
conducted. At a distance 
of six inches, or less, below 
the top of the brick-work, 
a cast-iron plate is inserted, 
in which is a square hole for the reception of the 
grate. A common stove-grate, four or five inches 
square, and fitting loosely into the cast-iron plate, is 
the kind generally used. A small opening, below 
the grate, leads into the ash-pit, in order to carry off 
the ashes and cinders. On the right and left of the 
fire, a wall of fire-brick is erected, six inches in 




20 MANUFACTURE OF STEEL. 

height, •which support an arch, also of fire-brick. 
This arch is movable, and consists of an iron frame, 
into which the fire-brick are firmly wedged. In the 
wall on the right hand is an opening, into which an 
iron trough, in the form of a hopper, is inserted, for 
the purpose of heating the coal before it is put on 
the fire. Fresh hard coal, when thrown suddenly on 
a hot fire, is liable to crumble into small pieces ; the 
heating prevents this, and keeps the fire open, and 
free from fine coal. The top of the hearth, or brick- 
pile, is covered by an iron plate. A fire of this kind 
is very advantageous for common smith-work; but a 
concentrated heat cannot be made in it. 

The fire-hearth represented in Fig. 1 is commonly 
twelve or sixteen inches wide, and six inches deep. 
The tuyere dips a little into the fire. The hearth is 
built of brick or stone, thirty inches high, and is 
covered, in whole or in part, by an iron plate. At 
the left side, an iron trough for coal, and a similar 
one for water, are usually inserted. An iron coal- 
trough is advantageous in working bituminous, and 
also hard coal. The coal in the trough is soaked in 
water, which qualifies it for roasting or coking, and 
affords the additional advantage of more readily dis- 
engaging the sulphur of the coal. For charcoal, a 
water-trough only is necessary. Forge-fires for large 



FORGING. 21 

work are generally very low — in some instances, but 
a few inches above the floor of the workshop. Over 
the fire is a light roof, or hood, of sheet-iron; or, 
over small fires, of boards. This hood gathers the 
smoke and gases of the fire, and conducts them to 
the chimney. The chimney should not be too small ; 
for a great deal of cold air draws into it with the 
smoke, and diminishes, in proportion, its capacity for 
draught. The flues to the stack are usually in the 
highest part of the hood ; but as this arrangement 
frequently leads to smoking, it is a good plan to have 
either an iron pipe or a brick channel leading from 
the upper flue down to the fire. The flue will then 
carry off all the gas and smoke from the fire, and 
also that from below the hood. This arrangement is 
indicated, in Fig. 1, by dotted lines. 

Portable forges are of great utility in ship-build- 
ing, on railroads, in laying gas and water-pipes, 
erecting steam-engines, and in many other branches 
of industry. Those most in use are called " truck- 
forges,' ' and are generally mounted on two or four 
wheels. These portable forges are usually built en- 
tirely of cast-iron, and are supplied with a leather 
bellows, a vice, and a small anvil. They are used 
for sharpening chisels, bore-bits, picks, blasting tools, 
stone-drills, the heating of rivets, and similar work. 



22 MANUFACTURE OF STEEL. 

Such an apparatus, for small work, answers all the 
ordinary requisites of a smith's forge. In fig. 6, a 
portable forge is represented, such as is generally in 
use. The cast-iron fire-hearth is mounted on a box, 

Fig. 6. 




or chest. The bellows are in the chest, and are pro- 
tected by it. The tuyere is a concave disk, with six 
or seven apertures. The chest may be made of wood 
or iron, and be either mounted on wheels, or carried 
by hand. The advantage of the treadle in the har- 
dening and tempering of tools may readily be per- 
ceived, as it leaves both hands free for operation; 
and such work is generally done single-handed. 

THE ANVIL. 

Next in importance to the forge-fire, is the anvil 
of the smith. This is not only of interest as a tool 
of the trade; but it is also a particular object of our 




FORGING. 23 

inquiry, because the steeling of the anvil is a matter 
of some importance. Anvils for heavy work are 
generally square blocks of iron, with steel faces. In 
many instances, however, it is merely a cast-iron 
block, with chilled face. The common smith's 
anvil is represented in fig. 7. It is made entirely of 
wrought-iron, and the* upper part, FK 7 

or face, is covered with hardened 
steel. The making of an anvil is 
heavy work, as the whole of it is 
performed by hand. Anvils vary 
in weight from one hundred to over 
five hundred pounds. For their manufacture, two 
large fires are required. The principal portion, or 
core, of the anvil — a square block of iron — is 
heated to the welding-heat, at a certain point or cor- 
ner, in one of the fires ; and the piece of iron which 
is to form a projecting end is heated at another fire. 
When the core and corner have both reached the 
welding-heat, they are brought together upon an 
anvil, and joined by heavy swing-hammers. In this 
way the four corners of the base are welded to the 
body, in four heats. After this, the projection for 
the shank-hole, and lastly the beak, are welded to 
the core. The whole is then brought into proper 
shape, by paring and trimming, for the reception of 



24 MANUFACTURE OF STEEL. 

the face. The steel used for this purpose is, or ought 
to be, the best kind of shear-steel ; blistered steel is, 
however, frequently substituted. The anvil and steel 
are heated in separate fires until they attain the pro- 
per temperature; the two sides which are to be 
welded are then sprinkled with calcined borax, and 
joined by quickly repeated blows of the hand-ham- 
mer. The steel generally used is half an inch thick ; 
but if it be only a quarter of an inch in thickness, 
the difference is unimportant, if the steel be good. 
Steel of an inferior quality, if too thick, is apt to 
fly, or to crack in hardening. 

The steeled anvil is next heated to redness, and 
brought under a fall of water, of at least the size of 
its face, and of three or four feet head. After har- 
dening, it is smoothed upon a grindstone, and finally 
polished with emery. Small anvils, such as are used 
by silver-smiths, gold-beaters, &c, are polished with 
crocus, and have a mirror-like face. 

The expensiveness of wrought-iron anvils has in- 
duced their manufacture, for particular purposes, of 
cast-iron. The common anvil, however, cannot be 
made of cast-iron \ for the beak would not be strong 
enough. None but anvils with full square faces have 
been successfully made of cast-iron ; these are either 
simply chilled by casting the faces in iron moulds, or 



FORGING. 25 

the face is plated with cast-steel. Chilled cast-iron 
anvils are not much in use ; they are too brittle, and 
the corners of the face will not stand. Cast-iron 
anvils with cast-steel faces, however, are a superior 
article, and in many respects preferable to wrought- 
iron ; the face is harder and stronger, though the 
beaks will not last as long. For purposes where a 
good face is essential, as for saw-manufacturers, cop- 
per and tin-smiths, &c, the cast-iron anvil with cast- 
steel face will be found to answer every purpose* 

The anvil is generally set upon the butt end of a 
large block of w T ood, oak being preferred. It is 
placed loosely upon it, being secured merely by a 
few spikes or wedges driven into the wood. Cutlers, 
file-makers, and those who manufacture small articles 
of steel, place their anvils upon blocks of stone, in 
order to make their foundation firm, prevent recoil, 
and give efficiency to light but quick blows of the 
hammer. In working soft metals, such as copper 
and its compounds, a layer of felt between the anvil 
and the block will be found of advantage. 



26 



MANUFACTURE OF STEEL. 



TONGS 

Form an important class of tools in the forge. 
There is so great a variety in their sizes and forms, 
that a description of the principal would occupy 
more space than we can devote to them. Still, there 
are but a few leading forms, the varieties of which 
arise either from fancy, or from the peculiar nature 
of certain work. The common or flat-bit tongs are 
represented in fig. 8, A ; they are of various sizes, 
from one foot to five feet long, and from a half to ten 
pounds in weight. The fire-end is made more or less 
open, according to the thickness of the articles to be 

Fig. 8. 




held with it. The bits, or lips, vary in width, and 
are often hollow, so as to fasten with more certainty 
to round iron and fagots. An oval ring, or coupler, 
is put upon the handles, or shank, to hold the tongs 
firmly to the work. Next in general utility to the 
flat-bit tongs, are the pincer-tongs, represented in 



FORGING. 



27 



fig. 8, B. The swelling on the lips, or fire-end, is an 
advantageous arrangement, particularly where short 
pieces of round or square iron are to be forged. To 
this class of tongs belongs also that form in which 
the bits are round, as in the nail-tongs. Another 
useful variety is the crook-bit, shown in fig. 9; it 



Fig. 9. 




serves particularly for small work in steel, because 
the rod may pass the nail. There are, besides these 
forms, basket-tongs, hoop-tongs, pliers, pincers, and 
numerous others. 



HAMMERS. 

An item not less important in a smithy than tongs, 
are chisels, fig. 10, A ; punches, B ; swages, C ; to 
which a bottom tool belongs, which is cut with its 
square tail, or shank, in the anvil. D, fig. 10, is a 
representation of anvil chisels. The above tools are 
either fitted to a handle which passes through the 



28 



MANUFACTURE OF STEEL. 



Fig. 10. 




eye, as in A and B, fig. 10 ; or, 
as in heavy work, the handle 
consists of a twisted hazel-rod, 
wound around the tool, C. These 
tools are all faced with steel, 
and are, in fact, cheaper if made 
entirely of that metal. Natural 
steel is preferable for this pur- 
pose to any other. Tongs made 
* ; ' of spring-steel are certainly 

more expensive at first, but are less costly in the end, 
than those of iron. Tools should never be heated 
red-hot, nor even allowed to become visibly hot; and 
if it should be necessary to bring tools in contact 
with heated iron, they should be repeatedly cooled, 
to prevent injury. 

Tools which may be made of iron, but which are 

better of steel, or at least 
faced with steel, are the 
set-hammer, fig. 11, A; 
and the heading-tool. The 
latter may be a single tool, 
as in fig. 11, B ; or a tool 
with many holes, C. 
Besides the tools we have named, an almost end- 
less variety is required in a blacksmith's shop, parti- 



Fig, u. 




FORGING. 



29 



cularly where machine-work is forged. Forges for 
the manufacture of hardware, or where steel is prin- 
cipally worked, are generally limited to a certain 
kind of tools, which have been found by experience 
to be the best adapted to the purpose. Thus, in the 
axe-factory, hammer-tongs are requisite — an instru- 
ment which is rarely found in any other establish- 
ment. 

Before leaving the consideration of forge-tools, we 
may make some additional remarks on the subject of 
hammers. The forms of this article are innumera- 
ble, each individual following the bent of his own 
fancy in constructing them. Undoubtedly, for cer- 
tain occupations, a peculiar form is requisite ; but 
there is no necessity for the endless variety of fan- 
ciful shapes the instrument is made to assume. The 
common hammer is shown 
in fig. 12; A, the eye or 
handle, being somewhat 
nearer to the pane, or nar- 
row edge, than to the 
head. The pane is a little 
rounded, as is also the 
head ; both are of steel, 
and hardened. The weight of the common hand- 
hammer of this form is from one to two pounds ; of 




30 MANUFACTURE OF STEEL. 

the ordinary smith's sledge (fig. 12), from five to 
eight pounds. A heavy sledge weighs twelve or fif- 
teen pounds, and a swing-sledge from twenty-five to 
thirty pounds. Some hammers have two flat heads, 
with the handle near one end ; others have spherical, 
or egg-shaped heads ; and others again have two flat 
panes set diagonally against the handle : these last 
are used in saw and hardware factories. Cutlers, 
and edged-tool makers generally, prefer the hammer 
with the handle at one end, or near the top, as in 
fig. 12, B. 

FUEL. 

The fuel used in forging steel is chiefly bituminous 
coal, which is preferable to any other. Where soft 
mineral coal cannot be obtained, charcoal is substi- 
tuted. Anthracite is unfit for the purpose. A close 
fire is necessary, where the oxygen of the blast is 
consumed, or converted into carbonic acid, or carbo- 
nic oxide. Open fires, like those of charcoal and 
anthracite, are not well adapted for heating steel, 
because a great deal of air passes through them un- 
burnt, which, in passing over the hot steel, deprives 
it, to some extent, of its carbon. Charcoal and an- 
thracite fires require a roof or arch of fire-brick, as 
shown in fig. 5, in order to secure the proper com- 



FORGING. 81 

tion of the air. In a fire of bituminous coal ? the 
roof may easily be formed of the coal itself. When 
damp, slack coal is thrown on the fire, in a layer of 
two or three inches thick, it will cake together, and, 
after the loose coal below it is burnt out, form a hol- 
low fire like a bakeoven ; the coke roof reflecting an 
immense heat upon the material below it. By no 
other means can a fire be made to possess so intense 
a heat as by the method we have described. In 
heating steel, particular attention should be paid to 
the purity of the coal, and to its freedom from sul- 
phur. Fine coal, wet, is less injurious to steel than 
coarse dry coal of the same quality. 

FLUX. 

Sand or other material, sprinkled upon iron when 
near the welding heat, serves to form a flux, or fluid 
glass, with the iron. This flux surrounds the hot 
iron or steel, and protects it against the impurities 
of the fuel, removing, at the same time, the coating 
of dry scales from the heated metals, and greatly 
facilitating the operation of welding. 

For welding steel to steel, and steel to iron, we 
have a variety of degrees of heat to deal with ; and 
the flux which serves to protect good iron, is insuffi- 



82 MANUFACTURE OF STEEL. 

cient to protect cast-steel — just as, on the other 
hand, the flux which fits cast-steel for welding, w ould 
be useless on iron. Impure wrought-iron will form 
a slag of its own material ; while good iron is pro- 
tected, as we have intimated above, by sprinkling 
fine sand over it ; but this method will not answer 
with steel, or where steel and iron are to be welded. 
The material used as a flux is to be applied shortly 
before the metal reaches the welding-heat, no matter 
how high or low that heat may be ; it will melt on 
the surface of the hot iron or steel, and last long 
enough to be brought to the anvil for welding. The 
slag flows off, or is forced out, in bringing the two 
surfaces together, and pressing them into close con- 
tact. If steel or iron is heated in contact with air, 
it burns, and forms a film of infusible magnetic oxide, 
which is remarkably refractory on steel. If two sur- 
faces are brought together which are partially co- 
vered with such infusible oxide, the metals cannot 
come fairly into contact, and of course the welding 
is imperfect ; it cannot be sound. After the flux is 
strewn on the iron, it is necessary to turn the metal 
constantly in the fire, otherwise the flux will flow to 
the lowest parts, and finally be lost. A better me- 
thod than that of sprinkling the sand on the hot iron 
is to roll the metal in the powdered flux, thus saving 



FORGING. 33 

the latter, and keeping the fire more free from 
clinkers. 

For welding iron, clean river-sand, or powdered 
sandstone, makes a good flux ; but it does not answer 
for welding steel, or steel and iron. For this pur- 
pose, borax is generally used. The common borax 
in crystals, as it is sold in the drug-stores, is com- 
posed of nearly one-half water. On heating these 
crystals in an iron pot, they dissolve into a clear 
liquid ; on further heating, the water is evaporated, 
and the residuum assumes the appearance of a spongy 
mass ; and by the continued application of heat, this 
mass is converted into a clear glass. This glass is 
therefore calcined borax; it is entirely free from 
water, and not very liable to absorb it. It should be 
prepared and powdered in advance, and always be on 
hand for use. Borax, thus prepared, is sufficient in 
almost all cases ; still, some workers in steel prefer 
a mixture of two parts borax with one of sal-ammo- 
nia, or three parts of the former with one of the lat- 
ter article. This compound is preferable for welding 
iron and steel. Borax alone is rather too fluid for 
iron, where it is to be welded to steel ; a more effi- 
cient flux for this purpose is well-dried and finely 
powdered white potters' clay — not common loam — ■ 
which has been moistened with salt water, or brine. 



34 MANUFACTURE OF STEEL. 

This clay makes a very fine flux and clean surface, to 
which steel readily adheres. There seems to be no 
apparent necessity for mixing sal-ammonia with bo- 
rax in welding steel. It certainly makes a more 
fusible slag ; but the chlorine of the ammonia, which 
combines with the slag — the ammonium being driven 
off — has a tendency to drive off the carbon from the 
steel, where it comes in contact with it, and convert 
such steel into iron. This conversion of the surface 
into iron does not facilitate welding, and leaves a 
vein of damask at the point of junction. 

If pure borax is too refractory, as is the case with 
some of the best kinds of cast-steel, an excellent flux 
may be produced by melting potash, or pearlash, 
together with pure dried clay, three parts of the for- 
mer and one of the latter, in an iron pot ; adding to 
the fluid mass, gradually, an equal weight of calcined 
borax. This flux should be finely powdered, and 
used like the borax ; it melts at a dark-brown heat, 
vitrifies the iron slag perfectly, and is not injurious 
to the steel. This metal rapidly deteriorates in 
quality if the atmosphere has access to it while hot ; 
a suitable flux, therefore, which protects it, and at 
the same time purifies the surface, is all-important. 



FORGING, 35 



WELDING 



Is that operation by which two pieces of iron or 
steel, or steel and iron, are heated, brought together, 
and intimately and permanently united under press- 
ure, or, as is more generally the case, under repeated 
blows of the hammer ; the junction being impercept- 
ible. As the welding-heat of different materials 
greatly varies, it requires, in many instances, a skil- 
ful and dexterous workman to perform the operation 
successfully. The blacksmith is to watch the heat 
on the two pieces minutely, and, if they both have 
their proper heat and flux, he pulls them out of the 
fire, and quickly unites them. If the pieces are 
separate, or united but imperfectly, the smith incor- 
porates both by his right hand and hammer ; and if 
the work is heavy, a second hand, or helper, assists 
in striking with a more or less heavy hammer. To 
weld natural steel, or natural steel and iron, is not 
difficult ; for it will bear almost as much heat as iron. 
Still, it should be kept off of the tuyere, and in the 
dark heat of the fire. If a small piece of steel is to 
be welded to a larger piece of iron, it is heated to a 
cherry-red, and the iron to a white heat, when they 
are temporarily united. The pieces, thus united, are 



36 



MANUFACTURE OF STEEL. 



Fi". 13. 




next exposed to a white heat, and sprinkled with bo- 
rax, (or, if German steel, with clay,) when the tem- 
perature is increased to a welding heat. If the steel 
is to be laid on a pick, crowbar, or any similar in- 
strument, it is drawn into that form, or a triangular 
bit, in which it is to be welded to the iron, as shown 

in fig. 13, A. Here the 
steel forms the tongue to 
a split joint, and the weld- 
ing is performed at the 
same heat, and in the same 
fire. In a similar manner, 
chisels, hammers, panes, 
* hatchets, axes, &c, are 

steeled. If shear-steel is to be welded in this way to 
iron, more attention and experience is requisite than 
for the welding of natural steel ; and the iron is 
drawn out to a greater length, so as to overlap and 
cover the steel more perfectly. Cast-steel requires 
still more caution, because it sustains still less heat ; 
and the iron must either overlap the steel entirely, 
and afterwards be cut or ground off; or the steel and 
iron should be heated in separate fires, in which case 
the butt-joint or scarf is preferable. 

In many instances, the edge which is to be steeled 
is made at first narrower than it is intended to be 



FORGING. 37 

when finished, and is afterwards drawn out when 
the welding has been completed. This method is 
adopted in the making of an axe. In fig. 13, B, is 
a representation of this process. The first operation 
is to bend a flat bar of iron, nearly as broad as the 
iron around the eye, and a little thicker. The eye 
is temporarily formed around a mandril, and the iron 
welded in the line A B, leaving two tails for the 
edges. The eye is then nearly perfected, using the 
mandril from both sides, so as to make it narrower in 
the middle than at the ends, which aids in securing 
the axe more firmly to the handle, and prevents its 
flying off, or slipping backward and forward. The 
head or poll of the axe is then laid on with steel of 
an inferior kind, and a slip of shear or cast-steel is 
laid between the two tails which are to form the edge. 
All three are then welded together, and drawn out, 
so as to form the broad side of the axe, which is now 
trimmed or pared with chisels, and hammered at a 
low heat to smooth it; after which it is hardened/ 
ground, and polished. 

Where the iron and steel are very thin, as in steel- 
ing shovels, the steel is laid between two thicknesses, 
and the whole welded and drawn out together. 

The butt-joint is used in welding a piece of steel 
to a flat surface, such as the face of an anvil, or the 
4 



38 MANUFACTURE OF STEEL. 

head of a hammer. In such cases, the piece of steel 
is forged to its proper shape before it is cut off from 
the bar, and fastened to the iron by notches, or by 
the drawn-up corners of the hammer-mould. It is then 
cut from the bar, and is ready to be welded. A more 
perfect method is to cut both surfaces coarsely with 
a rasp-like chisel, and fasten them together with a 
strap of wire ; this makes a better weld, particularly 
where the steel will not bear strong heat. Still an- 
other method is to nail the steel to the iron, as shown 
in fig. 13, C. A pin or spike is made of the steel by 
drawing it out in a thick round form, with a head as 
large and thick as is necessary to form the face. 
A corresponding hole is made in the iron mould, and 
the steel firmly spiked to it. The pieces, in this way 
temporarily united, are welded in one heat. 

Where large objects are to be faced with steel, 
such as anvils, beak-irons, and the like, two fires are 
required, that the iron and steel may be heated sepa- 
rately. If this cannot be conveniently done, the 
iron is first heated to a brisk white heat, and the cold 
steel is placed behind it, with a view of shielding it 
from the direct action of the fire. When the steel 
has in this way attained the welding-heat, the iron is 
ready, and the two may be united. When iron and 
steel are put at the same time into the fire, in a cold 



FORGING. 39 

state, the steel will be burned and spoiled before the 
iron is ready. Steel is so easily injured by heat, 
that the greatest care is requisite in exposing it to 
the action of fire. One of the most difficult opera- 
tions in steel, on account of its peculiar liability to 
injury, is the making of wire draw-plates. The pro- 
cess is most successfully performed by the French 
manufacturers. In this country and England, wire 
draw-plates are made by welding a plate of shear- 
steel to a plate of iron. In France and Germany, 
draw-plates are made by forming a crucible of the 
iron plate in drawing up the edges. In the cavity 
thus formed, hardened fragments of crude steel, 
white plate-iron, cast-steel, or the hardest natural 
steel, are driven in. The whole is then heated to 
the melting point of steel, and suffered to cool slowly. 
This melted steel forms a uniformly sound coating 
upon the iron. The face of the iron, before the steel 
is driven in, is well cleaned with a file, and of course 
a flux of borax applied. 

Flat edged tools, which are covered with a thin 
plate of steel on one side, such as carpenters' chisels, 
plane-irons, adzes, and instruments which require 
tenacity as well as hardness, are made by taking 
steel and iron, of a greater thickness than they are 
intended to be when finished, and drawing them out 



J 
40 MANUFACTURE OF STEEL. 

together, after welding, to the requisite dimensions. 
In a cast-steel factory, such chisels may be made by 
polishing the iron on that side where it is to be laid 
with steel, and, subjecting it to a gentle heat, the 
steel and iron may be firmly united by casting the 
former upon the latter. Both metals are here also to 
be drawn out together. 

The scarf-joint is but little used for welding iron 
and steel. If a rod of steel is to be welded to iron, 
as in stone-drills and similar tools, a cleft, or the 
split-joint, is preferred. The steel rod is then point- 
ed or drawn out into a chisel, and the iron rod cleft 
to receive it. 



BLISTERED STEEL. 

In the blacksmith's shop, blistered steel is more 
used than any other description. It certainly costs 
less at first, and is to some extent improved by forg- 
ing, or welding it to iron ; but when its inferior qua- 
lity is considered, and the labour necessarily expend- 
ed on many tools of common use, such as pick-axes 
and mattocks, it is evident that the difference in the 
cost of the steel will effect but a slight reduction in 
the price of the tool ; while its real value may be 



FORGING. 41 

much, enhanced by the use of a superior quality of 
steel. 

The price of common blistered steel is about five 
cents per pound ; and of good shear or cast-steel, 
sixteen cents. Now, as a pick scarcely requires a 
quarter of a pound of steel, it is evident that the 
difference in the expense is not quite three cents. 
Cast and shear-steel are both made of blistered steel; 
but the blistered steel commonly sold will not make 
good shear, and is certainly unfit for cast, steel. 
Good blistered steel — by which we mean steel made 
from good iron — cannot be sold at five cents per 
pound. Even if made of common charcoal bar-iron, 
it can scarcely be sold at that price. Swedish com- 
mon bar-iron commands almost as high a price as 
our ordinary blistered steel. Good cast-steel is made 
of a superior quality of Swedish iron, which costs 
nine cents a pound. Forging and hammering by a 
low heat will improve steel remarkably; but this 
improvement is scarcely perceptible, so far as tena- 
city is concerned. 



4* 



42 MANUFACTURE OF STEEL. 



SHEAR-STEEL. 

The most suitable steel for welding with iron, is 
the shear, or double shear-steel ; it will stand the fire 
better than cast steel, and, if of good quality, is but 
slightly inferior to it in hardness. The variation in 
quality is, however, very considerable, and great care 
is necessary in its manufacture. Edge-tools of a 
superior description arc manufactured from shear- 
steel ; which, if good, possesses the requisites of dur- 
ability and tenacity. 



CAST-STEEL. 

In the manufacture of articles composed of steel 
and iron, cast-steel is but seldom used ; yet, there is 
a description of cast-steel made expressly forwelding 
purposes, denominated welding cast-steel. It is fre- 
quently used in the manufacture of axes ; and some 
of the best now in use are made of this steel. It 
does not, however, although superior to shear-steel, 
assume the delicate edge and hardness of the best 
cast-steel. Very hard and fine varieties of cast-steel 
are but seldom, and then with extreme difficulty, 
welded to iron. In the manufacture of tools requir- 



FORGING. 43 

ing the use of cast-steel, such as cold-chisels, boring- 
bits, and tools for the turning and planing of metal, 
solid bars of cast-steel are employed ; this being, in 
many respects, the most economical method. 

WELDING STEEL. 

There is no difficulty experienced in welding to- 
gether two pieces of either the natural, German, 
blister, or shear-steel ; but, with cast-steel, the case is 
somewhat different. The first varieties of steel may 
be either welded one to the other, or two pieces of 
the same kind be welded together, in the usual way ; 
the only requisites being, a good forge, and the use 
of a flux of dry, pure clay. Steel of an inferior 
quality, may, by the use of a gentle heat, be drawn 
into small rods ; then fagotted, welded, and made into 
bars of any required weight and size. Good bitu- 
minous coal is almost indispensable for this purpose : 
forge-hammers are not necessary, the common sledge- 
hammer being sufficiently effective. 

Two pieces of cast-steel can be welded together, if 
proper care be used in the performance of the opera- 
tion. When two bars are to be welded lengthwise, 
they should be so tapered as to form a scarf-joint, and 
the scales on the tapered faces of the bars removed 
by the use of a file ; the faces of the bars may then 



44 MANUFACTURE OF STEEL. 

be roughened like a rasp, and covered with a paste, 
of borax-glass, or calcined borax; after which the 
bars may be finally bound together by iron wire. In 
this condition the weld may be exposed to the action 
of a fire which is nearly at a welding heat, and con- 
tains a sufficient quantity of ignited coal, to render 
the use of a blast almost unnecessary. When the 
steel has been softened to such an extent, that an im- 
pression can be made on its surface by an iron poker, 
and the borax has become perfectly fluid, the bars 
may be cautiously removed from the fire to an anvil, 
previously heated, and there hammered gently with 
a small hand-hammer. The iron wires, being at each 
end of the scarf, may be removed after the first heat. 
If the first heat does not prove sufficient, it may be 
again applied, with the same precautions. Small 
rods of steel undergo a similar process in welding, 
with the exception, that but little pains is taken to 
roughen the connecting faces of the rods ; they are 
merely filed, before being joined together, and the 
powdered borax applied to the joint when the rods 
are sufficiently hot to melt it. 

The East Indians weld their wootz, by a process 
similar to that just described. They taper their rods, 
file and roughen them, then bind them together with 
wire, and apply the borax when they are hot. 



FORGING. 45 

A subject of some interest, and certainly of great 
importance, is the welding of steel to cast-iron. 
This may readily be effected if the steel be clean, a 
little heated, and protected by a flux of calcined bo- 
rax. The cast-iron, of course, is to be very hot, if 
the objects are small ; or the steel is to be heated to 
a high degree. The chief difficulty in this operation 
consists in the hardening of the steel so welded to 
the cast-iron ; for, in chilling the hot steel and iron 
together, the latter will either become brittle, and 
crack, or cause the steel to fly. If strong and pure 
grey cast-iron be used, this is not so apt to occur. 
Perhaps the best iron for this purpose is the Pitts- 
burgh dark-grey charcoal pig. The best kind of 
cast-steel is that which hardens by the lowest heat. 
If grey, strong cast-iron is not overheated, it loses, 
on cooling, but little of its strength, and is not very 
subject to hardening. Cast-iron is similar, in this 
respect, to steel. A good tempering of the cast-iron, 
after hardening, as steel is tempered, will restore, in 
a great measure, its lost tenacity. 



46 MANUFACTURE OF STEEL. 



TEST OF THE QUALITY OF STEEL. 

The indications by which we distinguish good from 
bad steel are difficult to describe. Blistered steel, 
when the blisters are uniform in size, may generally 
be considered as of the best quality. Where there 
are but few blisters, and those of an irregular size, 
we should pronounce the steel of an inferior descrip- 
tion. Natural steel, German steel, and shear and 
cast-steel, are always bad if single sparkling crystals 
show themselves in a fresh fracture. Generally 
speaking, any sparkling steel is bad; it is merely 
hard, impure iron. Good hardened steel, on frac- 
ture, presents a dead silvery appearance, and is of a 
uniformly white colour ; in soft shear-steel, the frac- 
ture has a bluish tint ; and in soft cast-steel, it is of 
a greyish hue. In German and natural steel, the 
fracture has a soft bright grey tint, often inclined to 
fracture in the centre of the bar. 



THE HARDENING OF STEEL 

Is an operation which requires the exercise of 
some judgment. The usual method is to heat the 
steel to a certain point, and then plunge it suddenly 



FORGING. 47 

into cold water, tempering it afterwards. This method 
is undoubtedly the correct one ; but the degree of 
heat to which steel is to be exposed before cooling, is 
a matter of vast importance. Some steel — the na- 
tural, for instance — will bear a strong white heat, 
and a plunge into cold water, before it assumes its 
greatest hardness. Other steel, particularly fine 
cast-steel, will not bear more than a brown or cherry- 
red heat ; beyond that point it burns, and becomes 
brittle in hardening. It may safely be concluded, 
that steel which does not bear heat in forging, will 
not bear it in hardening. The heat at which steel 
falls to pieces, or melts, is too high for hardening, 
as steel hardened in such heat will fly or crack. The 
alterations manifest in steel after hardening, as com- 
pared with annealed steel, are the following: — Its 
volume is a little increased; the black scales which 
adhere to its surface fly off, and the surface appears 
clean, and of the colour and lustre of iron ; the frac- 
ture is brighter, and crystals are visible. Good steel, 
as we have said before, is silver-white, and is so hard 
that it will scratch pane-glass, and even a file. The 
cohesion, relative and absolute, is increased if the 
heat has not been too high before cooling. These 
are the chief characteristics of good steel, when 
hardened. 



48 MANUFACTURE OF STEEL. 

The phenomenon of hardening by sudden cooling 
is not peculiar to steel ; it belongs to all the alloys 
of metals, but is perhaps more characteristic of iron. 
There is not a bar of puddled iron in market which 
does not show all the phenomena of hardening and 
tempering as clearly as they are perceived in steel. 
Most of the charcoal wrought-iron, particularly the 
hot-blast, shows the same phenomena. There is no 
difference in kind, but in degree. 

None but the best and purest charcoal wrought- 
iron is uninjured after cooling. It is a true test of the 
quality of pure fibrous iron, if a bar, heated to the 
welding-heat, and suddenly plunged in cold water, 
does not harden or become, brittle. Most of the bar- 
iron, on subjection to such a process, becomes as 
brittle as glass, and presents the appearance of an 
accumulation of crystals, without apparent connec- 
tion. Such iron may be made more fibrous and 
strong by being fagoted, welded, and drawn. 

The assertion of some writers and artisans that 
any iron which hardens by cooling is to be consider- 
ed steel, is unfounded in reality; for every variety 
of iron in the market has this property. It is the 
tenacity and fine grain, or rather absence of grain, 
which distinguishes hardened steel from hardened 
iron. Bar-iron, hardened, does not derive much 



FORGING. 49 

strength from tempering ; while steel, on the other 
hand, does so to a high degree. 

While it is true that bar and wrought-iron are very 
sensitive to the process of cooling, it is so in a far 
higher degree with cast-iron. This description of 
metal, if suddenly chilled, becomes, in most cases, so 
highly excited as to crack, or fly. The hardest cast- 
iron, if pure, may be converted into malleable iron, 
almost equal to wrought, by judicious tempering. 
Such tempered cast-iron, however, cannot be welded ; 
it becomes brittle again if heated, and cooled in the 
air. Slow tempering, however, will restore such re- 
hardened cast-iron to its malleable condition. The 
best and purest varieties of cast-iron become so ex- 
cessively hard on refrigeration, that the finest cast- 
steel, in its hardest condition, can be scratched by 
it ; but this hardened cast-iron is very brittle in its 
smallest particles, and flies to pieces when in large 
masses. 

It is not possible to give any distinguishing mark 
between steel, wrought-iron, and cast-iron. A che- 
mical test is even inadmissible. As a general fea- 
ture, however, we may say, that cast-iron cannot be 
forged or welded, or at least very imperfectly ; that 
wrought-iron feels softer under the hammer than steel, 
in forging ; and that both impure wrought and cast- 
5 



50 MANUFACTURE OF STEEL. 

iron become very brittle in hardening. The united 
hardness and tenacity of steel are its characteristics. 
Good cast-steel, or any other variety, if not freshly 
annealed or hardened, and if free from fissures, will 
emit a sonorous silvery tone when a suspended bar is 
struck. Iron, particularly if good, emits a dull, 
leaden sound ; while cast-iron gives out a tone like 
that of a cracked instrument. 

Steel is superior to wrought or cast-iron in all the 
characteristic qualities of that metal ; it is stronger, 
tougher, harder, and more elastic than either cast or 
wrought-iron : indeed, it is iron in its highest per- 
fection. 

TEST OF STEEL. 

The surest test of the quality of steel is to draw 
a rod into a tapered point, harden it by a gentle 
heat, and break off pieces from the point. The de- 
gree of resistance to the hammer, which of course 
should be a very small one, is the test of the value 
of the steel. The best steel is that which, under 
this treatment, is found to be the toughest and 
strongest. 



FORGING. 51 



THE EXPANSION 

Of hardened steel is frequently the cause of great 
inconvenience to the workman. Steel welded to iron 
invariably draws the edge around, if it should be on 
but one side of the edge. It is also liable to become 
brittle when laid upon iron. These difficulties may 
be obviated by making the steel side convex, or tak- 
ing as little iron as possible. Files are never straight 
if made of natural steel, because that is in most 
cases but a mixture of iron and steel. In all cases 
where exactness after hardening is essential, the best 
kind of cast-steel is to be used ; neither blistered nor 
shear-steel can be trusted. The better the steel, the 
greater is its expansion in hardening. This expan- 
sion is in some measure reduced in tempering the 
steel, but not to the size in which it was received 
from the tilt. The expansion is greater where the 
steel has been heated to a high degree before refrige- 
ration, which may in some measure account for the 
brittleness of the metal when overheated. It is an 
important matter, in working steel, to keep it moving 
in the fire ; otherwise, on that side where the blast 
acts, it will lose its carbon, and will not shrink so 
much in hardening as those portions which have been 



52 MANUFACTURE OF STEEL. 

protected. A good method of protecting steel is to 
keep a film of calcined borax, or any other flux, 
around it while in the fire, or to cover it with a paste, 
as is done in hardening files and mint-stamps. 



REFRIGERATING FLUIDS. 

In hardening steel, the hardness is derived, not so 
much from the degree of heat to which the metal is 
subjected, as the degree of cold of the cooling fluid, 
and the manner in which the cooling is performed. 
Steel must be heated to a certain degree, to assume 
its greatest hardness ; if heated below that point, it 
will not become hard, no matter what kind of cooling 
fluid we employ, or in what manner we refrigerate. 
If the proper degree of heat be obtained, it is in 
our power to make the steel more or less hard, by 
choosing more or less cold water, or other fluid, for 
chilling it. Many plans of refrigeration, and many 
refrigerating fluids, have been advised for hardening ; 
but the most of them are of no practical utility. 
Pure well-water, taken fresh from the well, is the 
best element to cool in ; and it should be renewed at 
each operation. Well-water is everywhere, and at 
almost all seasons, of the same temperature ; and 
the smith should use this for hardening the steel, to 



FORGING. 53 

ensure success. Hard well or spring-water is prefer- 
able to that of a softer quality, and should, if possi- 
ble, be obtained. Steel treated in this way assumes 
its greatest degree of hardness, and may afterwards 
be tempered to any extent. 

The manner of cooling is of some importance. If 
hot steel is held quietly in cold water, it will not be- 
come as hard as may be desirable, because the steam 
formed on the hot surface will prevent its rapid cool- 
ing. A motion backward and forward, or up and 
down in the water, greatly increases the hardness. 
For hardening large objects, a current or fall of 
water is indispensable. 

The different degrees of heat required for harden- 
ing steel, accordingly as that steel is of good quality, 
or has been more or less worked, or is welded to iron, 
or is in large or small pieces, makes it exceedingly 
difficult, and indeed practically impossible, to employ 
hardening and tempering fluids at the same time. 
The surest method is to impart to the steel, in the 
operation of hardening, the greatest degree of hard- 
ness of which it is susceptible, and temper it after- 
wards. 

5* 



64 MANUFACTURE OF STEEL. 



HARDENING FILES. 

This process is one which has been brought to a 
high degree of perfection, and the experience gained 
in it has been advantageously applied in other 
branches of manufacture. A file, after being cut, is 
dipped in a fluid of a cream-like consistence. This 
fluid is composed of a saturated solution of common 
salt in water, thickened by flour or meal of peas or 
beans. This paste melts into a fluid slag, and sur- 
rounds the file, protecting it against the influence of 
the fire and air. The file is uniformly heated in a 
common smith's forge, or in a small reverberatory 
furnace, and plunged vertically (except half-round 
and fancy files, which have a more or less horizontal 
inclination) into cold spring-water. Saw-files, and 
sculptors' files which are of iron, are hardened by 
using animal-charcoal powder with the flour paste, 
or using it and salt water only. Coal for this pur- 
pose is made by putting leather, tanners' scraps, or 
horns and hoofs, in a tight iron pot, and exposing the 
whole to a cherry-red heat. The spongy, black, and 
shining coal is then to be finely ground for use. 

Rubbing a hot file, or any piece of hot steel, with 
a piece of charred leather, hoof, or horn, is not of 



FORGING. 55 

much use ; the glassy coating imparted by the salt is 
requisite to success. After files are hardened, they 
are brushed over with water and powdered charcoal, 
by which they become perfectly clear and metallic. 
After washing them repeatedly in fresh water to ex- 
tract the salt, they are dipped in lime-water, dried 
by the fire, and finally, while still warm, placed in a 
mixture of olive oil and turpentine. 



HARDENING OF NEEDLES, ETC. 

These are hardened in quantities of twenty-five 
pounds, which are heated together, and plunged in 
cold water, but so that almost each needle is sepa- 
rated from its fellow. Cutlery, such as knife-blades 
and similar articles, are held by the tangs, either in 
pairs or singly, heated to a cherry-red in the common 
forge, and plunged into cold water up to the tang. 
Sunk steel dies and mint-stamps are heated to the 
proper degree, and hardened under a current of fresh 
cold water, which is made to issue from a basin with 
great rapidity. 



56 MANUFACTURE OF STEEL. 



THE MAKING OF STEEL DIES 

For stamping coins or medals, for impressing bank- 
note plates, and copper cylinders for calico printing, 
is an art of much importance. It requires consider- 
able skill, time and expense, to make such dies ; all 
of which may be lost by imperfect material, or mis- 
management in hardening or tempering. The first 
requisite to success is the selection of the steel. 
Cast-steel is in all cases the best ; and it should be 
cast-steel which has been manufactured at a low 
heat, well-cemented, and made of the best materials. 
All steel, without an exception, contains veins of un- 
equal hardness. Natural steel is the worst in this 
respect ; blistered and shear are not much better ; 
and even the best cast-steel is not exempt from this 
characteristic. These veins are generally the cause 
of cracks. The steel, before it is selected for these 
operations, is carefully washed over with dilute nitric 
acid, or aquafortis, which causes the damask veins or 
spots to appear at the surface. Steel for dies should 
be entirely free of such veins, and more particularly 
of cracks and ash-holes ; for detecting which latter, 
a lens is required. 

In cautiously and slowly tempering steel, the hard 



FORGING. 57 

veins and spots may be concealed, especially if it has 
been tempered in charcoal ; but they will appear 
again in heating and forging the steel. These veins 
are less apparent in hardened steel, and would, in 
fact, be of but little consequence to the engraver, 
were it not for their greater liability to crack and fly 
than uniformly grained steel. Very much depends 
upon the die-sinker; he can spoil the best steel 
by faulty work ; that is, by overheating, or heating 
too often. Steel generally, and particularly this 
kind of steel, ought to be forged by the lowest pos- 
sible heat — as little as it can be done with, and no 
more. After the steel has been selected and forged 
into rolls, or dies of the desired form, it is annealed. 
The common way of annealing is to imbed the steel 
in coarse charcoal powder, in a crucible or iron pot, 
heat it to a cherry-red heat, and let the fire slowly 
go out, while the steel is in it. Animal coal is fre- 
4uently substituted for charcoal, or mixed with it ; 
but one is as good as the other : the time which the 
steel remains in the fire is generally too short for the 
mixture to act upon it. This annealing is of the ut- 
most consequence in the subsequent engraving ope- 
ration, and also in hardening, and ought to be 
extended to the proper period ; six, or even twelve 
hours, are not sufficient to anneal steel to perfection. 



58 MANUFACTURE OF STEEL, 

A low heat for twenty-four hours, or even twice that 
time, is not too much. 

When dies are engraved, they are next hardened ; 
but as the face of the engraving is to be faithfully 
preserved, it is protected by being covered over with 
a mixture of lamp-black and linseed oil. The whole 
is then imbedded in charcoal powder, in a pot, as in 
annealing, and finally plunged into cold spring-water, 
where it is rapidly moved about ; or it may be cooled 
under a current of water. 

As such dies will not safely bear twice hardening, 
the heat by which that particular kind of steel as- 
sumes its greatest hardness is to be ascertained by 
experiments upon a piece cut from the bar ; the die 
is then subjected to that heat. Dies and heavy 
bodies of steel are naturally exposed to cracks in 
hardening, resulting from its expansion. The inte- 
rior of a body of steel cannot shrink as much as the 
exterior, because it is protected by the surface steel. 
Nor can the hardening be of the same degree in the 
interior as at the surface. 

For the reasons we have given, we may conclude 
that all round bodies of steel are more or less 
fractured at the periphery; and experience, under 
all circumstances, will prove the correctness of this 
conclusion. 



FORGING. 59 

To prevent breakage as the result of these cracks, 
steel is to be tempered as soon as possible after har- 
dening, taking care that no impurities of any kind 
are in the water, which might fill the invisible cre- 
vices. Round bodies, such as dies and similar arti- 
cles, may be tempered by fitting a wrought-iron ring 
around them, first heating the ring to redness, and 
inserting the die or other object in it; the ring, in 
cooling, will firmly compress the die, and secure it 
against subsequent flying. When the die thus in- 
serted receives its proper temper, which is indicated 
by the colour, it is thrown into cold water, or water 
of 60° or 80°, and cooled. After tempering, the die 
is boiled in water for some hours, and suffered to cool 
slowly in the water. This process increases its tena- 
city considerably, and makes the hardening and 
strain more uniform throughout the body of the 
steel. 

The liability of dies and other engraved steel in- 
struments to break in hardening, or oftentimes hours 
after hardening, is rather a serious matter; for it 
may cause great loss to an artist. Every kind of 
steel is not liable to shrinkage, and consequently less 
liable to breaking. Steel containing much carbon is 
more liable to crack than where it is of a less carbon- 
iferous quality. The practice of imbedding steel in 



60 MANUFACTURE OF STEEL. 

animal or wood-charcoal, is therefore not judicious 
when steel is saturated with carbon, as is the case 
with the not-welding cast-steel. Steel with hard and 
soft spots or veins is also more liable to breakage 
than uniform steel. The latter steel generally con- 
tains less carbon than other steel of the same hard- 
ness ; slow tempering in hard charcoal will make it 
more uniform, and be a guard against cracks. Crude 
German steel does not shrink, and, if moderately 
heated and hardened, will not crack ; but if heated 
to such an extent as to acquire its full degree of 
hardness, it becomes very brittle. The steel made 
of this crude material shrinks and cracks, though not 
so much as cast-steel ; still, it never assumes that 
uniform hardness and tenacity which characterize the 
last-named variety. 

A number of plans have been devised to avert the 
danger of breaking dies, matrices and die-rollers, in 
hardening them ; but there is nothing better or more 
safe than slow and careful annealing, gentle heat in 
hardening, clear hard spring-water, and time and pa- 
tience in tempering. The roller-dies for bank-note 
plates, and copper calico-printing rollers — an inven- 
tion of the late Jacob Perkins, of Massachusetts — 
are hardened in this simple manner, the often very 
delicate engraving being protected by a chalk paste, 



FORGING. 61 

which admirably answers the purpose. Other means 
of protection, such as plunging the heated steel in 
oil, hot or cold, or in melted lead, or a composition 
of metals, are uncertain in their results, and liable 
to failure ; because, even if the oil, metals and heat 
are always the same, the steel is not — one kind of 
steel, or a particular kind of work, acquiring more 
hardness by the same treatment than another. 

HARDENING BY COMPRESSION. 

Among the various methods of hardening is that 
in spring-water, the most simple and most safe ; but 
there are some small articles to which we cannot give 
their highest degree of hardness and tenacity in this 
way. These are engravers' tools, surgical instru- 
ments, &c, which may be hardened to a high degree 
by being hammered with a very small hammer, well 
polished, on a hard, polished anvil. Delicate instru- 
ments assume by this practice a high degree of hard- 
ness, and a finer edge and more elasticity than can 
be given to them by any other mode of hardening. 
The conical holes in the wire draw-plate are hardened 
in the same way. 



6 



62 MANUFACTURE OF STEEL. 



ANNEALING. 

Of steel is a necessary operation in all cases where 
filing or engraving is to be done. The steel, as it 
comes from the anvil, is too hard for the file and the 
chisel, and must be softened or annealed before it is 
ready for the engraver. The common method of an- 
nealing is to heat the steel to a gentle redness off the 
tuyere, and leave it in the ashes of the hearth until 
cold. The slower this operation is performed, the 
more uniform and soft will the steel be. Tempering 
in a pot, imbedded in sand or chalk, or any dry pow- 
der, is preferable to the open fire. Some authorities 
recommend pastes and powders of various composi- 
tions for annealing ; but all such preparations are 
fallacious. Nothing more is requisite than heat, and 
the exclusion of atmospheric air or oxygen. 



TEMPERING. 

Steel properly hardened, is as hard as its peculiar 
quality permits it to become. In this state it is ge- 
nerally too brittle to be of any practical use, and it 
is necessary to temper it before it is exposed to any 
strain on its tenacity. Small tools are generally 



P0RGING. 63 

tempered after hardening, by covering the surface 
with a film of tallow or oil, then heating the steel 
until the oil diffuses a black smoke, or burns, or 
ceases to burn, and then plunging it in cold water. 
Picks, mattocks, blasting tools, and similar imple- 
ments, are tempered by heating the heavy part from 
behind the edge or point, driving the heat towards 
the point. One side of the edge being ground white, 
shows the tempering colours ; and when the proper 
colour is arrived at, the steel is cooled just at the 
point, but not the heavy iron behind it. Many me- 
chanics harden and temper their common tools in the 
same heat, by merely dipping the hot point or edge 
in cold water ; the heat of the heavier parts is then 
transmitted to the hardened edge, after it is removed 
from the cold water. When the proper colour is 
gained, which is ascertained by scratches of a dull 
file, the tool is cooled by dipping it in water. This 
latter process requires some experience, or the steel 
is apt to become either too hard or too soft, and 
require renewed hardening; which, of course, is 
injurious to the steel. 

Instruments which are designed to be very perfect, 
are polished all over, and then heated to the temper- 
ing colour. Small articles, such as knife-blades, are 
set in large numbers with their tangs in a heavy steel 



64 MANUFACTURE OF STEEL. 

or iron plate ; that plate is then heated, and, when 
the proper colour is on the blades, each is singly 
plunged into cold water. Needles are tempered in 
masses, by burning oil upon them. Saw-blades, and 
large articles generally, are tempered in hot sand ; 
the sand being heated to a certain point, which is 
tested by the thermometer. Sometimes this precau- 
tion is not taken ; and the course then is to watch 
the articles until they obtain the requisite colour, 
when they are hardened in either air or water. 

The colours to which steel can be tempered may 
be approximately stated thus : The hardest articles, 
which do not require much strength, should assume 
a faint yellow ; surgical instruments, razors, and en- 
gravers' tools, a pale straw-colour ; knives, cold chi- 
sels, and bore-bits, yellow ; chisels, shears, hammers, 
anvils, and some varieties of saw-blades, dark yel- 
low ; axes, plane-irons, carpenters' tools generally, 
and most edged tools, brownish purple ; table-knives, 
weapons, and scissors, purple ; watch-springs, saws, 
and augers, light blue ; common saws, heavy watch- 
springs, carriage-springs, and springs generally, 
blue ; articles which require strength, but in which 
hardness is a secondary consideration, dark blue. 
Beyond dark blue the colour is black, and the steel 
is perfectly soft. 



FORGING. 65 

These colours are only approximating the sub- 
ject ; for the various kinds of steel will show a dif- 
ferent degree of hardness in being tempered to the 
same colour. The naturally soft steel should have 
a shade or two less temper than that of the hardest 
description. 

Many propositions have been made by scientific 
men to harden steel in fusible metal compositions, to 
avoid tempering; or to temper the steel in such 
metals ; or to temper in a bath of lead heated to a 
certain degree, measured by the thermometer, &c. 
All these things are very well as scientific recom- 
mendations, and we shall speak of them in another 
place. They are of little practical value, however ; 
for it is not the absolute degree of heat in harden- 
ing, or the difference in heat and cold, or the degree 
of the tempering bath, which decides the superiority 
or inferiority of hardened instruments of steel. The 
quality and description of the steel, the manner and 
mode of working it, the form and the fuel, are mat- 
ters which influence the degree of heat in hardening, 
and also in tempering. In all cases of this kind, the 
simplest way of working is the best ; the skill and 
dexterity of the worker in steel is a better guarantee 
of success than all the artificial compositions of cool- 
ing and tempering mediums. A good, skilful work- 
6* 



66 MANUFACTURE OF STEEL. 

man knows by the bearing of his steel under the 
hammer what degree of heat is most suitable for the 
kind of steel under his management, and will harden 
and temper according to his own convictions. 



DAMASCUS STEEL. 

To imitate or make Damascus steel in the forge by 
welding together steel and iron which has been bound 
in fagots, or any other form composed of thin rods, 
is an experiment generally attended with but ill suc- 
cess. The quality of steel, as we shall explain here- 
after, depends so much upon the quality of the ore 
and iron from which it is made, as not to offer any 
hope of success in the attempt to make good steel in 
the forge. Damascus gun-barrels are made by weld- 
ing strips of iron and steel together; but in. harden- 
ing such compositions, the advantages are small in 
respect to tenacity, and the loss is considerable in 
hardness. 

Gun-barrels, which are of course not hardened, 
are certainly superior when made in this way to those 
forged in any other manner ; but this is not the case 
with edged instruments. A kind of Damascus steel 
for weapons is still imitated by some French cutlers ; 



FORGING. 67 

but it is so expensive a process, and the blades are 
so slightly, if at all, superior to those of the ordinary 
manufacture, that this is more of a curiosity than any- 
thing else. 

CASE-HARDENING 

Is that process by which the surface of iron is 
converted into steel. This is a very useful art, and 
deserves to be more cultivated than it is at present. 
In this process, the surface of iron may be made 
harder than the hardest steel, and still retain all its 
malleability. Steel, when hardened, is brittle, and 
tools or keys of steel are liable to break. If case- 
hardened, however, they combine all the advantages 
of steel and iron. 

The articles to be case-hardened are to be well 
polished ; and if the iron is not quite sound, or shows 
ash-holes, it is hammered over and polished again — 
the finer the polish, the better. The articles are 
then imbedded in coarse charcoal powder, in a 
wrought-iron box, or pipe, which should be air-tight. 
A pipe is preferable to a box, because it can be 
turned, and the heat applied to it more uniformly. 
The whole is then exposed for twenty-four hours to 
a gentle cherry-red heat, in the flue of a steam-boiler, 



68 MANUFACTURE OF STEEL. 

or in some other place where the heat is uniformly 
kept up. This makes a very hard surface, and, on 
large objects, one-eighth of an inch in depth may 
be thus obtained. If so much time cannot be given 
to the operation, and no deep hardening is required, 
the articles are imbedded in animal charcoal, or in a 
mixture of animal and wood coal ; four or five hours' 
heat will make a good surface of steel. If a single 
article, a small key, or any other tool, is to be hard- 
ened, the coal must be finely pulverized, and mixed 
into a paste with a saturated solution of salt ; with 
this paste the iron is well covered and dried. Over 
the paste is laid a coating of clay, moistened with 
salt water, which is also gently dried. The whole is 
now exposed to a gradually increased heat, up to a 
bright red, but not beyond it. This will give a fine 
surface to small objects. In all cases, the article is 
plunged in cold water when heated the proper time, 
and up to the proper degree. 

A quick mode of case-hardening small objects is 
that by prussiate of potash. The iron is well pol- 
ished, and heated to a dark-red heat ; it is then 
rolled in a box containing powder of the yellow prus- 
siate of potash, or sprinkled with it ; the powder will 
melt on the surface, and the iron is then heated to a 
bright-red, and plunged in cold water. The powder 



FORGING. 69 

of the prussiate is obtained by exposing the crystals 
to a gentle heat in an open iron box, or pot, for the 
purpose of evaporating the water contained in them ; 
the remainder is a white powder. Some persons 
recommend the mixing of one-third camphor with the 
prussiate. As the camphor melts at a lower heat 
than the prussiate, and causes it also to melt, the 
whole operation can be performed at a lower heat, 
which is certainly an improvement. Calcined borax 
has also been proposed to be mixed with the prussiate ; 
but we do not know with what effect it operates. To 
mix prussiate in clay, as recommended by some, is 
not of much use, as it requires too much labour to 
put the clay around the article ; in these cases, the 
above recipe of coal, salt and clay, is all-sufficient. 

In the operation of case-hardening there is not the 
slightest difficulty; any degree of hardness may be 
given, and almost any depth. The addition of salt, 
bone-ashes or bone-black, animal charcoal, hoof, horn 
or leather, to the charcoal powder, will regulate the 
degree of hardness ; and the time of its exposure to 
the action of heat must be governed by the depth of 
steel required. 

While the performance of the operation is simple, 
it is not so easy to select the proper kind of iron. 
If the iron is of coarse fibre, the hardened and pol- 



70 MANUFACTURE OF STEEL. 

ished surface will be unsound ; if it is impure, it will 
be brittle after being hardened. The surest way is 
to select a very fine, close-grained iron, heat a piece 
of it a little beyond the heat by which it is to be 
hardened, and plunge it into cold water. If it re- 
tains its fibre and malleability, and is free from ash- 
holes, it may be selected as fit for the purpose. 

Edges, however hard they may be, are never good 
if made of case-hardened iron ; it is not in the na- 
ture of the materials, nor of the process, to produce 
such a result. 

The most expeditious method of case-hardening is 
to imbed the article in borings of grey cast-iron, in 
a sheet-iron box, which may be open at the top, and 
covered with fine dry sand. These borings are a better 
conductor of heat than charcoal, and the article is 
therefore very soon covered with a coating of steel. 
A very little salt may be added to the borings ; or a 
mixture of borings, charcoal, bone-coal, animal coal, 
scraps of horn, hides, leather, and other materials 
of the kind, may be used to advantage. 



VARIETIES OF STEEL. 71 



CHAPTER II. 

VARIETIES OF STEEL. 

Among the numerous kinds of steel, we recog- 
nize but few which are at present current. These 
are blistered steel, shear-steel, cast-steel, and Ger- 
man steel; the other varieties are simply modifi- 
cations of these. The first is almost the only quality 
at present manufactured in the United States; a 
small portion of cast-steel is made, but so small as 
to be scarcely worth mentioning. About eight thou- 
sand tons of iron are annually converted into steel, 
in this country ; of which about five hundred tons are 
melted into cast-steel, and the rest is principally used 
as blistered steel for springs and saws, and consumed 
by the manufacturers themselves. German steel 
also was formerly manufactured, particularly in New 
Jersey and some parts of Pennsylvania ; but we are 
not aware that this is now the case. Little of the 
American steel is brought into market. 

There are some kinds of steel which have but an 



72 MANUFACTURE OF STEEL. 

historic interest for us — such as the Asiatic Damas- 
cus steel, Indian wootz, and similar varieties — which, 
as belonging to the manufacture, and therefore de- 
serving of notice, we shall mention in subsequent 
pages. Such steel, however, is not found in our 
market as merchandise. 



WOOTZ. 

The most ancient steel historically known appears 
to be the Indian cast-steel, or " Wootz." The ancient 
Egyptians imported steel from Asia and Bombay, 
via Persia — the great high roads of the Indian trade. 
At the time of the invasion of India by Alexander 
the Great, when the Greeks made their weapons of 
bronze, wootz wds manufactured in India. English 
travellers in modern times have been very inquisitive 
as to the mode of manufacturing wootz among the 
Asiatics, and also as to the material from which it is 
made. They have succeeded very well; but the 
operation is of such a nature, that we cannot derive 
much practical benefit from it. 

Wootz is made of magnetic iron ore, such as we 
have in great abundance in the States of New York, 
New Jersey, and Pennsylvania. This ore, which is 
naturally mixed with quartz, and which appears to 



wootz. 73 

be very impure — for nearly half of it is quartz — is 
finely pulverized, and the impurities winnowed away. 
The fine ore is then moistened with water and formed 
into cakes, to prevent its running down through the 
hot coal in the smelting furnace. The furnace is of 
the form of one of our cupolas, about four feet high, 
and two feet wide at the bottom by one at the top. 
The furnace is charged with charcoal, and thoroughly 
heated. The breast or front opening, which is about 
a foot wide, is then closed and dried, and a certain 
quantity of ore is laid upon the hot coal, at the top 
of the furnace. The furnace is kept filled with fresh 
coal, and the blast applied. This is made by two 
goat-skins, which, being worked alternately by hand, 
make a uniform blast. The nozzles are of bamboo 
sticks, fastened to the neck of the skin; the tail, 
and a similar bamboo, forming the valve, which is 
shut and opened by hand. The tuyere is made of 
clay. 

From three to four hours generally finishes the 
blast. The breast-wall is then broken open, and the 
iron from the interior of the furnace removed. The 
metal, then in the form of a cake, is beaten down 
with wooden mallets, and cut so as to show the inte* 
rior, but not broken ; in which form it is ready for 
the market. The ore yields about fifteen per cent. 
7 



74 MANUFACTURE OF STEEL. 

of iron. It is from the iron thus obtained that the 
wootz, or Indian steel, is made. This iron is cut into 
small pieces, and charged with about ten per cent, of 
dry wood in crucibles. The crucibles are made of 
fire-clay, mixed with the charred husks of rice. One 
pound of iron is generally a charge for a crucible : 
it is covered with a couple of green leaves, and 
a layer of fire-clay rammed on closely. This cruci- 
ble, when charged, is gently dried to expel all the 
water and hydrogen. From twenty to twenty-four 
of such crucibles are then built, in the form of an 
arch, into a small furnace, and covered by charcoal 
all around, when fire is applied, and this at last urged 
by blast. Two or two and a half hours of blast ge- 
nerally finish the work ; the crucibles are then re- 
moved from the fire, and allowed to cool. When 
cold, the crucibles are broken up, and the steel is 
found in the bottom, in the form of a cake. Good 
cakes show a radial crystallization on the upper sur- 
face, and are free from holes and blisters. An im- 
perfect fusion shows a rough surface, or honeycomb 
appearance, with lumps of malleable iron. In this 
form the steel is brought into market, and corrected, 
in re-melting the cakes, by fusing many together, 
and running them into ingots like common cast-steel. 
It is said that wootz which has been re-melted in this 



DAMASCUS STEEL. 75 

way is superior for the manufacture of cutlery to 
any cast-steel. 

In this process of converting iron-ore, first into 
iron, and then into steel, we find all the elements of 
our present mode of doing the same business. The 
blast-furnace of the Asiatics is, on a small scale, our 
present blast-furnace ; though, owing to their imper- 
fect operation, the ore which yields them but fifteen 
per cent, of iron would, in our hands, yield at least 
sixty or seventy per cent. Instead of using, as they 
probably do, twenty tons of fuel, we use but two 
tons for the same quantity of iron. The Asiatic 
mode of converting iron into steel is the mode we 
follow at the present day ; the only difference being 
that we divide the operation into cementing and melt- 
ing, while they perform both in the same heat. It 
is not the place here to inquire what is the prefera- 
ble mode of manufacturing steel ; but we shall con- 
sider the subject thoroughly in some of our subse- 
quent pages. 

DAMASCUS STEEL — DAMASCUS BLADES. 

These are terms applied to a kind of steel which 
shows a variegated, watery appearance, on the pol- 
ished surface. It is originally from Asia, and the 



76 MANUFACTURE OF STEEL. 

scimitars, or swords, chiefly from Damascus, where 
the art of manufacturing blades appears to be best 
understood. The excellent quality of this cutlery, 
particularly scimitars, has long been proverbial ; no 
other steel has been found to equal it in tenacity and 
hardness. The process by which this steel is worked 
is not known; it is a secret faithfully preserved 
among those who are engaged in the manufacture. 
European artisans and scientific men have endea- 
voured to imitate the Asiatic damask, but with ill 
success ; the form and appearance of the steel has 
been imitated, but its quality has never been equalled. 
French manufacturers, particularly, have wasted a 
great deal of time and means in such attempts. The 
probable cause of the superior quality of this steel is 
in the raw material, the ore ; and it may in some 
measure be attributable to the skill of the artisan who 
manufactures the blades. It has been ascertained 
that the ingots of wootz of which the oriental Damas- 
cus is made come from Golconda ; and it is therefore 
probable that it is manufactured in the same manner 
as the Indian wootz before described. This supposi- 
tion is strengthened by the great value of the blades, 
and the peculiarities of the wootz. 

Alexander Burnes, in his journey to Cabool, tells 
us that a scimitar was shown him in that city which 



DAMASCUS STEEL. 77 

was valued at five thousand rupees, and two others 
at fifteen hundred each. The first was forged in 
Ispahan, in the time of Abbas the Great. The pe- 
culiar value of this weapon consisted in its uniform 
damask; the " water' ' could be traced upon it, like 
a skein of silk, the entire length of the blade. Had 
this "water" been interrupted by a curve or cross, 
the blade would have been of little value. One of the 
cheaper weapons was also of Persian make ; its water 
did not run straight, parallel with the blade, but was 
waved like a watered silk fabric. It had belonged to 
Nadir Shah. The third scimitar was a Khorassan 
blade ; there were neither straight nor waved lines in 
it, but it was mottled with black spots. All three 
blades were strongly curved, but the first more so 
than the others. They tinkled like a bell, and were 
said to improve by age. How very interesting these 
accidental remarks of the traveller are in respect to 
the manufacture of steel generally, we shall show 
hereafter. 

Imitations of Damascus steel are made daily, and 
have been made for the last fifty years ; and there is 
no doubt some good has resulted from these experi- 
ments. The real value of the imitations, however, 
is quite limited, and we shall say but little about it. 
Damask steel has been made and is made of such 
7* 



78 MANUFACTURE OF STEEL. 

perfectly developed veins, by welding together bun- 
dles of small slips of steel and iron, or steel of dif- 
ferent kinds, that all imaginable figures which can be 
delineated by hand have been imitated. The smooth 
water, the waved water, a torsion of the damask, and 
the spotted damask, have all been produced ; names, 
letters, inscriptions, leaves and flowers, have been 
represented ; but all these pretty things do not make 
Damascus blades of equal quality with those of 
Asiatic manufacture. It appears the Persians do not 
use so much skill in forging, but depend upon the 
elements. Recent experiments have shown that when 
blades are cooled slowly, as by swinging them in the 
air, a damask is produced on steel highly charged 
with carbon. This, however, is nothing new ; for 
the next best blades to those of oriental manufacture 
— the blades of Solingen — have been hardened or 
tempered in that way for centuries. It is certainly 
the most perfect mode of hardening steel, where 
tenacity also is desirable. 

It is said that one hundred parts of soft iron, and 
two parts of lamp-black, melted together, make a 
fine steel, of great strength. It is also said that 
equal parts of cast and wrought-iron turnings make 
a fine steel, of damask quality, which is superior for 
arms and edged tools. There is no doubt that, by 



DAMASCUS STEEL. 79 

such means as the foregoing, an imitation of the ap- 
pearance of damask steel may be effected ; but it will 
depend entirely on the quality of the steel, the iron, 
the cast-iron, the lamp-black, or the crucibles, whe- 
ther the resemblance will extend to the quality of the 
steel. Impure materials will, under all circumstances, 
make bad steel ; and if we have good, pure iron, we 
can make good steel in a cheaper way than that 
proposed. 

Some experiments have been made by melting 
together cast-iron, carbon and alumina, so that the 
molten iron contained aluminum. A portion of this 
aluminous iron was melted together with blistered 
steel, and the result was a steel very much like the 
wootz ; it showed damask very distinctly. Other 
manufacturers than those who made the experiments, 
however, assert that aluminum is no necessary part 
of Damascus steel. 

The damask veins may be made to appear on the 
surface of polished steel by washing it with a thin 
solution of sulphuric or muriatic acid, which will dis- 
solve the softer parts of the steel first, or those parts 
which contain least carbon ; after which the steel is 
washed in fresh water, and oiled, or waxed. We do 
not know whether or not the orientals bring out their 
damask in a similar way ; but are inclined to believe 



80 MANUFACTURE OF STEEL. 

that they do not. In some parts of Europe — Spain, 
Portugal, and portions of Italy — steel is buried under 
ground, often for months together, to improve its 
quality. May not this be the manner in which the 
orientals etch their blades ? 



GERMAN STEEL. 81 



CHAPTER III. 

GERMAN STEEL — NATURAL STEEL. 

In a few places, such as the east of Europe, and 
in Russia, steel is made in wolfs, or blue-ovens ; a 
kind of high furnace, or blast-furnace, in which a 
certain quantity of ore is melted ; the iron gathers in 
the hearth, and is then broken out and cut to pieces, 
by which the iron and steel are separated. It is thus 
a similar process to that followed by the Asiatics in 
making wootz, except that the apparatus is larger, 
and more iron is made at a time. This process is of 
little practical value, and is possessed of merely an 
historic interest. 

German steel derives its name, not from being of 
a peculiar quality, though that is the case, but from 
the manner in which it is manufactured. It is al- 
ways made of pig or plate iron, in forges where 
charcoal is used for fuel. Natural steel may be made 
of grey pig-iron, or of white plate-iron ; the latter is 



82 



MANUFACTURE OF STEEL. 



Fig. 14. 



the cheapest method, and produces the best steel. As 
we cannot make that peculiar white plate-iron, which 
the Germans call steel-iron, and which is made from 
the sparry carbonate of iron as its ore, because we 
have no such ore, we shall not say much about the 
manufacture of steel from such peculiar ore 

The fires or forges used for making this kind of 
steel are the common forge-fires of the smithy, gene- 
rally known as the charcoal forge-fires. They resem- 
ble the bloomery fires, the only difference being in 
some minor points of dimension. In fig. 14, such a 

forge-fire is represented, in a 
section through its tuyere. 
The chief object here is a 
stack or chynney, A, which 
is from twenty to forty feet 
high, and of the width inside 
of two feet or more, so as to 
absorb all the heat and smoke 
from the fire. B is the hearth 
J! or forge-fire, the dimensions 
of which vary according to 
the quality of the crude iron, the quality of steel to 
be made, the kind of charcoal used, the description 
of blast, and the peculiarities of the workman. We 
shall allude to these dimensions hereafter. This 




GERMAN STEEL. 



83 



hearth forms a square, or often an oblong, basin. 
The four sides are cast-iron plates ; in many cases, 
however, they are made of stones, or fire-brick. The 
bottom is formed of sandstone ; and it depends very 
much upon the composition of this sandstone, of 
what quality the steel will be. C is the tuyere of 
copper, which may be replaced by iron ; but a water 
tuyere, as is used in the iron forge, will not do here. 
D is the blast-pipe and nozzle ; the latter is to be 
moveable, and is therefore connected with the main- 
pipe. Hot blast cannot be applied here as is done 
in making iron. The blast-pipe, which is five or six 
inches wide, and made of tin-plate or sheet-iron, is 
provided with a throttle valve, so as to regulate the 
blast at pleasure, according to the requirements of 
the work. E is merely a column of iron, wood, or 
stone, designed to support a sheet-iron hood, or roof, 
which is to protect the workman, and carry off the 
heat. The chimney, foundations, and walls, may be 
built of either brick or stone, 
as most convenient. 

In fig. 15 the same forge- 
fire is represented from 
above. It is here assumed 
that two fires are at the 
same stack ; if necessary, 



Fig. 15. 




84 



MANUFACTURE OF STEEL. 



more than two may be erected to one chimney. This 
figure requires but little explanation. A is the chim- 
ney, B B the fire-hearths ; in fact, the references 
used in fig. 14 denote the same objects here. 



THE BLAST 

Is made by strong blacksmiths' bellows, of which 
there should be two pair, driven by water-power, or 
any other force ; or the bellows may be of wood, in 
the form of the common leather bellows, or either 
wooden or iron cylinders. A powerful blast is not 
so requisite here as in making wrought-iron. The 
best blast for the purpose would be a good fan, such 
as is now generally in use. 



Fig. 16. 



Fig. 17 





Fig. 16 represents a fan of the improved form, 
which makes at least twice the pressure of the old 



GERMAN STEEL. 85 

fan ; the engraving shows a horizontal section through 
the centre shaft of the vanes. Fig. 17 is a vertical 
section of the fan. The shaft is made of steel, the 
four vanes of copper, and the cross arms which carry 
the vanes are of brass or wrought-iron. The four 
vanes are enclosed in, and fastened to, two rings of 
sheet-copper, which form with the vanes a round box, 
open at the periphery and at the centres. The air 
enters at the centre, and is expelled at the periphery. 
This round box, which is composed of the axle, the 
cross, the four vanes, and the two sides in one piece, 
moves in a cast-iron case of the form of the common 
fans. The blast is driven out at some convenient 
place in the circumference of the outer or stationary 
case ; it makes no difference where, or at what place 
in the periphery, this is done. The inner case fits as 
closely as possible with its rims to the cast-iron case. 
The two cases are bored and turned on the lathe, 
where they meet in the centre. 

FORGE-HAMMERS. 

Besides forge-fires, there are to be hammers or 
tilts, for forging and refining natural steel. Up to 
the present period, we have had no better machinery 
than the old, well-known tail-hammer ; that is, a tilt 



86 



MANUFACTURE OF STEEL. 



which is chiefly built of wood, and where the moving 
power is attached to the tail-end of the hammer-helve. 
For a series of years, improvements in the old form 
of construction have been proposed and executed, but 
with ill success ; there is hardly anything known that 
can be considered an improvement on this primitive 
mode. 

Fig. 18 shows a side view of a common tilt, as it 
is used in this country, England, Germany, &c. 
There are often slight deviations in the form, but in 
the main it is everywhere the same. This figure also 

Fig. 13. 




explains itself; it shows the hammer, whose helve, 
of dry white oak or hickory, is from six to seven feet 
long, according to the weight of the hammer. The 
hammer-head should be of wrought-iron, and its face 



GERMAN STEEL. 87 

plated with one inch thick of cast-steel, well hardened 
and polished. 

For the forging of scythes, files, and other small 
articles, the hammer-head is of about fifty pounds in 
weight ; for drawing loups and refining, the weight 
is increased to two hundred pounds. The head is 
secured to the helve by wooden wedges, into which 
wedges of iron are driven. The eye of the helve is 
tapered on both sides, like an axe, which prevents 
its flying off. The wooden wedges are used for the 
protection of the helve and head. At the tail-end, 
the helve is provided with a strong iron ring, or hoop, 
firmly fastened to the helve. This hoop (sometimes 
there are more than one) holds a flat steel bar, which 
rests upon the helve, and upon which the cams or 
wipers strike. Below the helve, at the tail, is another 
iron or steel plate, held by the hoops, which strikes 
upon a piece of timber so laid as to spring back when 
pressed down by the hammer. This wooden spring 
is provided with a steel or iron plate, upon which the 
tail end of the hammer strikes. 

The practice, in lifting the hammer, is not to raise 
it slowly, according to the speed of gravitation, but 
to strike the tail of the hammer with great speed, and 
fling the hammer so that the wiper merely touches 
the tail. The hammer, in being moved with great 



88 • MANUFACTURE OF STEEL. 

velocity, touches the spring-timber under the tail, and 
the head is forced down by this recoil upon the hot 
steel on the anvil. The lift of these hammers is in 
most cases but a few inches; of the heaviest, but 
eight or ten inches. The force is chiefly produced 
by recoil. The speed of these hammers is unusually 
great, the heaviest kind making from two hundred to 
two hundred and fifty strokes per minute. Small 
hammers, for forging thin or small articles, make 
from four to five hundred strokes in the same time. 



THE FACES 

Of the hammers are from five to nine inches long, 
and from one and a half to two and a half inches 
wide The anvil is in most instances made of wrought- 
iron ; and a hardened steel plate, a little wider than 
the face of the hammer, is dovetailed and wedged in, 
as represented in fig. 19. The 
^^ anvil may also be made of cast-iron, 

^—j^lllljl^ and the cast-steel welded to it when 
— *H casting the block; an operation 

f Wm^ now very well performed in a fac- 

p^ tory in Trenton, N. J. The anvil 

is fastened by wedges in a heavy 
wooden log, which extends eight feet or more under 



GERMAN STEEL. 89 

ground ; so deep, that the earth is sufficiently solid 
to resist the farther depression of the log. If the 
ground should be too loose, swampy or sandy, piles 
should be driven, and the anvil-log set upon them. 
The anvil-log is frequently three feet or more in dia- 
meter, taking the butt-end uppermost, and is provided 
on both ends with strong iron hoops, which prevent its 
splitting. The position of the anvil-log is a serious af- 
fair in erecting a hammer ; if not well supported below, 
it will sink ; and a rock foundation is equally bad, for 
on it the log is crushed. To protect the wood, and 
afford stability to the anvil, the vertical log is pro- 
vided with a cast-iron crown, or chabote, which weighs 
from one to three tons. This chabote is fastened 
upon the log, and the anvil is set in a square hole on 
its upper face. This iron block receives the momen- 
tum of the strokes, and protects the anvil-log against 
sinking and crushing. Stone foundations for the 
anvil are expensive and insecure. 



THE PILLARS, 

Or housings in which the fulcrum of the hammer 
is fixed, are in most cases made of good hard wood. 
There are also cast-iron frames for this purpose ; but, 

considering the first cost of such iron frames, and 

8* 



90 



MANUFACTURE OF STEEL. 



their short durability, there is nothing gained in 
using that metal for these standards. We will not, 
therefore, further allude to iron standards, but pro- 
ceed to describe the construction of those which are 
made of wood. 

The two pillars of the housing are made of good 
white oak, eleven or twelve feet long, ten or twelve 
inches thick, and about twenty-four inches wide. In 
case such heavy timber cannot be had, two sticks are 
bolted together by iron screw-bolts. About three or 
four feet of the two pillars are above ground. The 
part below ground is provided with cross timbers, 
as shown in fig. 20, which is a view of the hammer 

Fig. 20. 




from above. The timbers, A, BB, are from five to 
six or more feet long, and are fastened to the pillars 
by screw-bolts, which are from eighteen inches to 
tw r o feet apart. Below the surface of the earth, 
the cross-timbers are securely held down by heavy 
blocks of stone, and firmly walled into the ground, 



GERMAN STEEL. 91 

so as to prevent all possible motion of the tim- 
bers. This stone-work can scarcely be too heavy. 
Above ground, the space between the pillars is open, 
to receive the fulcrum of the hammer. The fulcrum, 
F, which is fastened to the hammer-helve by wedges, 
is made of cast-iron with chilled points, or of wTought- 
iron with steel points. In the wooden pillars, two 
cast-iron plates of hard metal are inserted, with some 
half a dozen holes to receive the points of the ful- 
crum. These plates are from two to three inches 
thick, eight wide, and sixteen inches long. They are 
inserted in the wood so as to be moveable ; for the 
adjustment of the hammer and anvil faces is regu- 
lated by the shifting of these plates. Wooden wedges 
are used for fastening these blocks, as iron screw- 
bolts do not resist the raking force of the hammer. 
In making these plates large, so as almost to cover 
the interior of the pillars, and providing them with 
a sufficient number of screws, ^e no doubt gain an 
advantage ; they are certainly preferable to the small 
plates. There is no need of large holes for the screw- 
bolts, if the plates are provided with various centre- 
holes. The pillars above ground are held together 
by three iron bolts, which serve in the mean time to 
hold the pillars close in the points of the fulcrum. 
Hammers are generally worked by water-power, 



92 MANUFACTURE OF STEEL. 

partly because the speed necessarily varies, and such 
variation can be most conveniently regulated by a 
small water-wheel — partly also because the first out- 
lay is generally less for a water-wheel than for a 
steam-engine — but chiefly, because the running cost 
is lower by the water-wheel. 

The tap-ring is invariably a cast-iron hoop, of six 
or eight inches wide and three or four inches thick, 
in which there are from eight to twenty-four wipers. 
The cams, or wipers, are either of cast-iron, wrought- 
iron, or (if small) of steel, wedged by wood into the 
square holes of the ring. The ring is to be of at 
least four feet diameter ; it may even be larger. 
Small tap-rings are very injurious to the hammer and 
its frame. 

The shaft is sometimes of wood ; but cast-iron is 
the best. It may be made hollow, to increase its 
strength with the same weight. The water-wheel, 
which is on the same shaft with the tap-ring, is either 
of wood or iron, but is to be strong in both cases, as 
the reaction upon the wheel from the hammer would 
soon shake it to pieces, if not well braced. The 
water-wheel is in most cases seven or eight feet in 
diameter, seldom more than nine or less than five 
feet. The size of the water-wheel depends partly on 
the head of water, but chiefly on its quantity. If 



GERMAN STEEL. 93 

there is an abundance of water, the pressure is prin- 
cipally relied on ; where economy is to be exercised, 
the weight gives the power ; but in most cases both 
weight and pressure are used. Where steel is drawn, 
or hardware manufactured by force-hammers, the 
speed of the driving power must be absolutely in the 
command of the workman, as it is impossible to work 
thin steel to advantage with a uniform rate of speed. 
Drawing steel rods, and similar work, may be done, 
after some experience ; but the forging of scythes, 
sickles, and such light articles, cannot be done, with 
a due regard to excellence, by a uniform speed of the 
hammer. 

For the reasons we have given, a wheel for a 
steel-hammer should always have a head of five or 
six feet of water, which is led in such a manner upon 
a breast-wheel that it may be used either by weight 
or by pressure. A wheel of seven feet diameter 
should work by ten revolutions, and must be capable 
of making twenty-five. This will give, with a tap- 
ring of four feet diameter, and sixteen wipers, from 
one hundred and sixty to four hundred strokes, which 
difference is required for small hammers and light 
work. For large hammers, the extremes need not be 
so great. Each hammer should have its own inde- 
pendent speed ; for it is the varying heat and thick- 



94 MANUFACTURE OF STEEL. 

ness of the work which renders the variation in 
speed necessary ; and this differs at each hammer. 

These irregularities in speed cause, of course, a 
great loss of power, either of water or steam ; and 
in consequence of this loss, a great many attempts 
have been made to connect a series of hammers with 
one stationary power, and regulate the speed by belts 
and drums. In the New England States, these at- 
tempts, in some instances, have been successful ; but 
in Europe they have generally failed. The cause of 
failure is the inability to produce a sudden change of 
speed in the belt. 

The arrangement we have described is by no means 
the most perfect ; but it is approved and simple, and 
the best adapted to show the principles involved. 
The sudden jerks given by the hammer to the shaft 
and wheel render it necessary to make both as strong 
as if of one piece. Heavy masses are well applied ; 
but it is ill policy to go beyond the necessary weight. 
The momentum of the wheel and shaft is then an 
obstacle to sudden changes of speed, which are 
always necessary. 

If a wheel of seven feet makes twenty-five revolu- 
tions, and the cam-ring is four feet, it will impart 
a speed of five feet per second to the wipers. The 
speed of the hammer-head is to be greater than that 



GERMAN STEEL. 95 

of gravitation in the first second, or sixteen feet. If 
the fulcrum is set one distance from the tail, and 
three distances to the head, the next wiper will catch 
the tail before the head is on the anvil, if there are 
but six inches stroke. The fulcrum is to be at one 
for the tail and four to the head, which will give 
sufficient speed and recoil. 

Force-hammers of a great variety of forms are in 
use, in this country as well as in Europe; but, of all 
the variety, there is none better adapted for forging 
steel and hardware than the tail-hammer we have 
described. 

MAKING STEEL. 

The operation of making natural steel is very 
similar to that of making charcoal blooms of pig 
iron. On melting grey pig or mottled iron in the 
charcoal forge, it frequently happens that a part of 
the iron is naturally ready for forging, while the 
other portion is at the bottom, in a liquid state. The 
portion of the charge which is soonest ready is a mix- 
ture of crude steel and fibrous iron, and may be said 
to be spring-steel. 

In all our remarks on natural or German steel, we 
wish it to be understood that we speak but with 
reference to cold-blast charcoal pig-iron. Hot-blast, 



96 MANUFACTURE OF STEEL. 

anthracite, or coke-iron, will never make an article 
that can with propriety be called steel, or answer the 
uses of that metal. 

We have said that in melting grey pig or mottled 
iron, we frequently find a description of natural 
steel. This may be of a tolerably good quality, but 
it is never suitable for edged tools, or for any pur- 
pose where strength is required. If such lumps of 
steel are from good, strong pig-iron — that is, iron 
which makes a strong bar-iron, and is smelted of pure 
ore, such as magnetic and specular ore — they are of 
use for common blacksmiths' purposes, and particu- 
larly for springs and agricultural implements. They 
are drawn out into square or flat bars, of one inch 
square, or less, and then fagoted and welded, by 
which the steel is greatly improved. If it should be 
hard and show no fibres after the first refining, it 
may be piled once more, when it will become still 
more uniform. 

The steel made in this way is, in reality, not steel ; 
it is simply a kind of hard WTOught-iron, which is 
brittle or tenacious according to the quality of the 
pig-iron from which it is obtained. This is the most 
simple form, the first step in the approach to the 
making of steel. A hard, brittle wrought-iron, made 
directly from the ore, no matter how good that ore 



GERMAN STEEL. 97 

may be, is never more than a brittle, impure, cold- 
short bar iron. 

The foregoing process of making steel is the result 
of imperfect work in the forge, which never ought to 
happen. If the pig-iron is of such a quality as to be 
suitable for steel, it is better to rebuild the fire, and 
prepare it for the work of a few days, or a regular 
course of steel-making. 

When steel is to be made of Nos. 1 or 2 pig-iron, 
the common charcoal forge in which bar-iron is re- 
fined, is altered so as to adapt it to the making of 
steel. The principle which governs in the manufac- 
ture of natural steel is, the regulation of the refining 
process in such a manner as to delay the completion 
of the refining, and still expose the iron to a high 
heat. The pig is melted opposite the tuyere, instead 
of above it, as in making iron ; or, if very grey pig, 
it is melted above the blast. The principal requisite, 
however, is a hot fire, that the iron may be melted 
down as speedily as possible. 

The fluid pig-iron is in this way brought below the 
tuyere, where it is worked gently by hot tools to pre- 
vent its boiling. If the iron boils below the tuyere, 
it will not make steel, but short iron ; the Swedish 
bars are made in that way. The iron should never 
be allowed to boil ; and if it chills on the bottom, 
9 



98 MANUFACTURE OF STEEL. 

and is very hot, it is brought opposite to or above the 
tuyere, but so far off as not to be touched by the 
blast. The principal difference in making iron and 
steel is, that iron is to be worked diligently, and is 
never worked too much ; while in making steel, the 
work must be regulated by a practised judgment. 
Steel must be protected against the blast ; still, the 
fire and iron are to be very hot, and uniformly hot. 
It is never broken up by a bar ; but the cake of iron 
retain the form it receives on melting and flowing 
into the hearth ; the blast being so directed as to 
heat it uniformly. 

The practice of making steel is somewhat different 
if the pig-iron should be No. 2, or white iron. We 
have little or no ore which will make a good white 
iron for steel. The only useful ore which we know 
of is the Missouri iron mountain ore — a particularly 
good quality of per-oxyde — or the specular ore of 
Lake Superior, of which we know but little. There 
are other good ores in New Jersey, viz., the Andover 
specular ore ; but this is not used at present, although 
in the last century steel was made from it. Such 
white iron — that is, No. 2 iron, or that made by a 
heavy burden in the blast-furnace — is melted entirely 
above the tuyere, in the strongest heat and a strong 
blast. By the time such iron arrives at the bottom 



GERMAN STEEL. 99 

of the hearth, it is almost converted into steel. A 
low heat and weak .blast will make iron instead of 
steel. In this instance, the pig-iron is selected with 
particular reference to steel. Open or mottled No. 2 
is reserved for wrought iron ; and only the close, 
compact, crystallized, clean pigs are selected for steel. 
The pigs or plates for steel are not to be cast in 
chills, nor in damp sand ; they are cast in heavy pigs, 
either in dry sand, or, what is better, in charcoal- 
dust. If, during the melting-in of this pig-iron, some 
of it is converted into fibrous iron, it does not mat- 
ter; it may be reconverted into steel by giving a 
strong blast, and keeping such blast off the iron ; it 
will then once more dissolve and unite with the crude 
iron, or steel. 



FLUXES. 

In all cases, the addition of fluxes to the melted 
iron, such as hammer-slag or scales, cinders of former 
heats, iron-ore, and similar matter, is to be avoided. 
Though such fluxes may be good in making iron, 
they are worse than useless in manufacturing steel. 
A fluid cinder should always be around the cake of 
iron, or steel ; if the fire works too dry, it is better 



100 MANUFACTURE OF STEEL. 

to throw some fine fire-clay, or fine white sand, on 
the cake, to make cinder. Anything else, no matter 
what its name may be, is injurious to the steel, and 
should be most carefully avoided. 

PIG-IRON, 

No. 3, or white iron with much carbon, of a quality 
suited to the manufacture of steel, is not made in 
this country. We have no ore for making such iron. 
White iron highly carbonized, as it is frequently 
made in blast-furnaces when the operations are dis- 
ordered, is the least useful for steel. We know of 
but the black magnetic and specular ores, in this 
country, which are of any use for the manufacture 
of natural steel. These ores are to be smelted by 
charcoal and cold-blast, and the blast-furnace should 
not be overburdened, or the product will be cold-short 
wrought-iron, and not steel. 

The method of working Nos. 1 and 2 pig-iron dif- 
fers essentially from that pursued in working No. 3. 
The dimensions of the fire-hearth and arrangement 
of the blast are also very different ; so that Nos. 1 
and 2 cannot be worked in a hearth intended for 
No. 3. As, however, we have no No. 3 pig-iron 
which is suitable for the manufacture of steel, we 
shall confine our remarks to Nos. 1 and 2. 



GERMAN STEEL. 101 



THE MAKING 

Of steel requires great heat. For this reason, the 
fire is made more flat ; the bottom is raised, and the 
tuyere not dipped so much as in making iron. Grey 
iron admits of more dip of the blast than mottled or 
■white pig. When working the latter, the wind is to 
be kept off the bottom, or the steel cakes altogether 
too fast. Grey pig requires less blast than mottled ; 
white iron should have a strong blast, and the highest 
possible degree of heat. Grey iron made from the 
same ore as the white, will make a better steel than 
the latter ; but it requires more labour and attention 
than to work white iron. 

Under all conditions, a high heat is desirable ; but 
as grey pig works rather slowly, the heat is dimi- 
nished ; this often arises from the quality of the pro- 
duct. The heat and blast should be uniform, as well 
during the melting, as after the metal has caked in 
the bottom. The tuyere or nozzles are sometimes 
shifted; but this is an imperfect way of mending 
matters, and the necessity for it should be avoided. 
Two nozzles, and a broad half-round or oval tuyere, 
will be found of great advantage. A round tuyere, 
with one round nozzle, is not adapted to the purpose, 
9* 



102 MANUFACTURE OF STEEL. 

and should not be admitted into a forge for the ma- 
nufacture of steel. 

The more the iron is inclined to give up its carbon, 
which is always the case with the best and purest 
kinds of iron, the more should the work be hurried, 
and the higher should be the heat. The bottom of 
the fire is to be clean and dry, every drop of cinder 
tapped off, and every particle of scoria removed, be- 
fore the iron is melted down. This is a standing 
rule, which must be rigorously adhered to in all 
cases ; but more particularly with white and good pig 
than with grey or bad iron. 

Pig-iron which is grey, or which works too slowly, 
may be improved by melting it down, and gradually 
introducing small quantities of good, pure scrap-iron, 
cut up finely, and freed from rust or scales. These 
scraps are to be of old iron, or old steel ; fresh scraps 
are not of much use. The scraps dissolve in the 
fluid iron, and are put into it quite hot, almost at a 
welding heat, to prevent the cooling of the mass. 
Impure or rusty scrap-iron, and cold water, are to be 
avoided; they make the iron boil, and give it a 
fibrous quality. By avoiding what we have desig- 
nated, the heat may be increased without any fear 
that the iron will boil ; it will assume a pasty, thick 
appearance, and soon become strong enough to be 



GERMAN STEEL. 103 

shingled. Reducing the blast, diminishing the heat, 
or turning the blast upon the melted iron to accele- 
rate the process, are bad practices ; they either make 
cold-short and brittle or fibrous iron. 



FORM AND DIMENSIONS OE HEARTH. 

The form and dimensions of an approved hearth 
for converting grey pig-iron into steel are as follows 
(we refer to fig. 14) : The square fire-hearth is thirty- 
four or thirty-six inches wide from the tuyere to the 
opposite side. The cast-iron plate at the tuyere is at an 
inclination of about 10° or 12° to the hearth, which 
is about one and a half inch on twelve inches high. 
The opposite plate is as much inclined out of the 
hearth, to permit a more easy access to the loup of 
steel. The timp-plate, or that plate nearest the work- 
man, which is the front part of the drawing, is vertical, 
but is a few inches higher than the other three plates. 
Its opposite plate is thirty inches distant. In the 
timp-plate is a round hole of two or three inches dia- 
meter, for letting out cinder and Fig. 21. 
scoria. A copper tuyere, very much 
tapered, as represented in fig. 21, is 
inclined about 12° into the fire, and 
projects about four inches into the 




104 MANUFACTURE OF STEEL. 

hearth ; at its narrowest end, it is one and a half by 
half an inch wide. The distance of the tuyere from 
the timp-plate is twenty inches, and from the back 
plate ten inches. The cast-iron plates around the 
fire are from one and a half to two and a half inches 
thick ; and as they are always covered with charcoal 
dust, or braize, there is not much danger of their 
burning out. The height of the tuyere above the 
bottom is five inches — never more than six. The 
height above the tuyere is variable ; it may be four 
or five inches, for very hard coal : fine coal, or soft 
coal, make nine or ten inches necessary, at least at 
the timp and opposite the tuyere. The bottom, one 
of the most important portions of the fire, is a sand- 
stone slab of two or three inches thick ; it rests upon 
an iron base, but better upon sand. This bottom is 
better if in one piece, but may answer if of several 
pieces. On the quality of these stones the success 
of the operation mainly depends. Coarse sandstones, 
in which much iron, lime and magnesia are found, 
are not good; they will make iron, but no steel. 
Stones in which there is lime are also unsuitable. A 
fine-grained, slaty sandstone, in which there is much 
clay, and which does not effervesce with acids, is the 
best for the purpose. Fire-brick are not good ; they 
do not last, and cause great waste in iron. If the 



GERMAN STEEL. 105 

stones for the bottom are of the right sort, the work 
progresses faster, and the steel is better. Good 
stones will last eight or twelve heats ; bad ones often 
but one or two. If the stones are gently dried and 
heated before they are put in the hearth, they last 
much longer ; two or four weeks should be allowed 
for drying. The advantage of having the bottom in 
one piece consists in the fact that it will last longer, 
and that the work-bars are not retarded in passing 
over the crevices, as in a hearth composed of several 
pieces. The crevices between the stones, where a 
single slab of sufficient size cannot be obtained, are 
filled with fire-clay, or fire-proof sand ; clay is pre- 
ferable to sand. 



MANIPULATION. 

A fire-hearth prepared in the above manner is 
covered on the inside with a layer of clean charcoal 
dust, which is well-rammed in, partly to protect the 
iron sides, and partly to have a non-conductor of heat 
between the melted or hot steel, and the cast-iron 
plates. The bottom stone is left bare, or only co- 
vered with some fine charcoal. The hearth is then 
filled with charcoal, and the fire gently urged by the 
blast. Upon the dust of the far-off plate, some 



106 MANUFACTURE OF STEEL. 

pieces of steel from the last heat may be laid, partly 
to secure the dust, and partly to re-heat these pieces 
for subsequent drawing. 

When the fire is well burnt through, and every 
part of it warm, the pig-iron, about one hundred and 
fifty pounds, is laid opposite the tuyere, upon the 
charcoal, so that it may be uniformly heated, without 
melting. At this stage of the operation, a little 
hammer-slag, or fine cinder, is strewn over the fire, 
so as to make a slight film or covering of cinder over 
the bottom, by which the bottom is protected, and 
the heat augmented. 

During the heating of the pig-iron, the pieces of 
steel from the last heat are brought above the tuyere, 
and heated for shingling and drawing. In the mean- 
time, a piece of pig-iron, weighing about twenty 
pounds, is placed in such a position opposite the 
tuyere, but out of the blast, as to cause it to melt 
rapidly. The fire is constantly fed with fresh coal. 
Water on the coal is to be avoided. At this stage 
of the process, all the blast is given which the bel- 
lows will make ; for the fire cannot be too hot ; the 
iron must become perfectly liquid before it reaches 
the bottom. If the iron is grey, and the trial by 
crowbar shows it to be thin, the blast may be slack- 
ened ; but if it is not quite grey, and there should 



GERMAN STEEL. 107 

be any doubt as to its fusibility, the blast may be 
urged on. 

The iron in this condition is stirred by means 
of a small crowbar ; but as soon as it assumes a thick, 
paste-like appearance, a second piece of cast-iron, of 
say thirty pounds in weight, should be rapidly melted 
in ; this will make the iron in the bottom quite fluid 
again, even if it has become chilled or stiff. The 
working in the bottom is now continued until the 
iron becomes pasty, or stiff; and if it works too 
slowly, some fine iron scraps, which have been pre- 
viously heated above the tuyere, may be added. The 
cinder in the bottom, if there should be any, is to be 
let out each time the mass feels stiff, and is ready for 
another melting ; there is no necessity for cinder in 
the bottom at this period of the process. 

Care should be taken that the metal in the bottom 
does not harden, and assume the appearance of 
wrought-iron, as in such case the stones are injured, 
and it is absolutely impossible to make steel. Should 
this hardening take place, the fire must be strenu- 
ously urged by the blast, and another portion of pig- 
iron, of thirtv or fifty pounds in weight, melted down. 
Each addition of pig-iron is intended and expected 
to make the whole mass in the bottom liquid again ; 
if it does not, there is something wrong. 



108 MANUFACTURE OF STEEL. 

Grey pig-iron, after having melted and reached the 
bottom, is inclined to boil upon the slightest stirring. 
If it contains much carbon, there is no harm done by 
a little boiling ; but if the crude iron is mottled, it 
is advisable to avoid the ebullition of the fluid mass. 
Boiling may be prevented or stopped by an increase 
of heat and a suspension of work, and also by keep- 
ing the bottom free from slag, or cinder. Iron 
"which is inclined to boil should be melted by day- 
light, and the bottom kept clear of cinder. During 
the melting, the blast must be kept off its surface. 
Some stirring in the hot mass is always necessary, in 
order to bring it to a uniform quality. The pig-iron 
is melted in successive portions, until the whole of it 
is down. The last or two last melts do not generally 
restore the whole of the steel cake in the bottom of 
the hearth to a fluid state ; they are apt to cut into 
the centre, and spread over the surface of it. This 
should be avoided by all means ; for the raw iron will 
penetrate between the bottom and the mass of steel, 
forming new cast-iron in the lower part, and wrought- 
iron of the upper part of the loup. The rule to be 
strictly adhered to in working the fire is, to melt the 
crude iron down in small portions, and let the next 
melt always cover the cake ; otherwise the blast will 
convert into wrought-iron those portions which are 



GERMAN STEEL. 109 

uncovered. The last melts of pig-iron are performed 
as quickly as possible, under the influence of a strong 
blast ; for if the steel cake is exposed too long to the 
blast, most of it will be converted into iron. It de- 
pends very much on the dexterity of the workman 
whether, of the same materials, he makes good steel, 
inferior steel, or iron. Low heat and slow work 
invariably make fibrous or hard cold-short iron ; too 
great heat and too much blast generally make a very 
hard, but brittle steel. All water, cold or wet bars, 
damp coal, and slag to accelerate the process, are to 
be avoided if a good steel is desired. 

The termination of the process is shown when the 
surface of the cake begins to give indications of con- 
version. The surface is then scraped off the cake 
with a crowbar, and held before the tuyere. If it 
resists a high welding heat, it is time to stop the 
blast. 

Hot steel is always of a darker colour than fibrous 
iron in the same heat ; and an experienced workman 
can perceive, by this difference, when the cake is 
ready. If the scale scraped off the cake melts be- 
fore the hot fire at the tuyere, it is evident that the 
mass is not yet done ; the scale must neither melt, 
burn, nor turn white, like iron. The cake, when well 
done, feels slippery to the touch of a bar ; if it feels 
10 



110 MANUFACTURE OF STEEL. 

soft, it is not yet ready ; and if it feels rough, it is 
time to stop the blast, as that roughness is an indica- 
tion that the mass is about to be converted into iron. 
After stopping the blast, coal and coal-dust are re- 
moved to the hearth by a scraper, the steel cake 
cleared of cinder and dust, and then permitted to 
remain for a while to cool, before it is taken out. 
When red-hot yet, or so far cooled as to be strong 
enough to be lifted without breaking, a sharp flat 
crowbar is driven through the tap-hole in the timp- 
plate, and the cake is lifted off the bottom. Should 
it adhere to the bottom, or to the tuyere-plate, as 
will sometimes happen, the crowbar is driven in by 
the force of a sledge-hammer. 

THE CAKE 

Is almost of a round form ; it is brought to the 
tilt, and cut into six or eight segments, which 
are of course in the form of a triangle. It is natural 
to expect that the circumference of the cake will be 
more of the nature of iron than of steel, and the in- 
ternal part inclines more to cast-iron than to either 
steel or fibrous iron. The triangles, whose base is 
formed by the periphery of the cake, and which are 
drawn out into square or flat bars while the melting 



GERMAN STEEL. Ill 

of crude iron is going on, make bars whose ends are 
inclined, the one to wrought-iron, and the other to 
cast-iron, while the middle portion is the "best part 
of the steel. These bars are generally forged into a 
square form, if uniformly hard steel is required ; if 
spring-steel is the object, flat bars may be preferable. 
As soon as the bars are drawn, they are thrown into 
cold water, to be chilled and afterwards broken. 
This hardening of the crude steel is by some per- 
sons thought necessary for the purpose of observing 
the fracture, and classifying the steel accordingly. 
But it is not strictly necessary, and is certainly very 
injurious to the steel, particularly if it should be de- 
ficient in carbon. A far better method is, to cut or 
shear the bar of crude steel into three lengths, and 
call these Nos. 1, 2 and 3 steel. A good forgeman 
knows perfectly well, w T hile he is drawing the bars, 
whether he has fibrous iron, cold-short iron, or steel. 
The hammer-man's judgment is sufficient, and the 
danger of hardening the bars may and should be 
avoided. 

When the cake is permitted to get too hard, before 
another portion of pig-iron is melted in, by scraps or 
by blast, no steel can be expected ; the cake will con- 
sist principally of iron. If the cake should be too 
soft or cold when a fresh melt comes down, cold-short 



112 MANUFACTURE OF STEEL. 

iron or bad steel is the result. If the process is not 
conducted with the requisite experience, it may hap- 
pen that the steel cake will be crude at the seam, 
and fibrous in the centre. 



EXPENSE OF THE PROCESS. 

The manufacture of steel in this way is not a very 
cheap operation. To make a ton, from good pig- 
iron, requires at least four hundred bushels of char- 
coal ; if the iron should be of an inferior quality, a 
still greater consumption of coal is necessary. Soft 
charcoal is preferable to hard coal in this, as in every 
other part of the process of manufacturing steel. 
The loss on iron is seldom less than thirty or thirty- 
three per cent. ; the. very best pig-iron never, under 
any circumstances, yields more than seventy-five per 
cent, of crude steel. 

One fire, supplied with two hands, may refine and 
draw, in the course of a week, from a ton to a ton 
and a half of steel. The yield of a fire may be aug- 
mented by using wrought-iron scraps freely ; two, or 
even three tons per week, may be thus produced ; 
but this requires good pig-iron, good scraps, and good 
workmen. Scraps of puddled iron, no matter of 



GERMAN STEEL. 113 

what kind, are useless ; they should be of the very 
best and purest charcoal iron, large quantities of 
which may be had at the charcoal forges, or at the 
gun factories. 



THE GERMAN METHOD 

Of making steel is to use cast-iron derived from 
the smelting of carbonate of iron, or sparry ore. We 
cannot make steel in that way, and are compelled to 
use grey or mottled iron for the purpose. The pro- 
cess in use in Sweden and Northern Germany was 
formerly practised in this country. The art among 
the Germans is highly cultivated, and is practised in 
a variety of forms, with a view to vary the quality 
and quantity. The processes are also, of course, 
modified by the peculiarities of the material and the 
workmen. On account of their many advantages, 
the Germans are enabled to make cheaper natural 
steel than we can. It is not of much use to describe 
their manipulation, for we can neither imitate nor 
improve upon it ; and to describe it merely for the 
purpose of showing the principle, would be a waste 
of time. 

The heavy expenses attending the manufacture of 
10* 



114 MANUFACTURE OP STEEL. 

steel have given rise to numerous attempts at im- 
provement ; but, thus far, very little has been accom- 
plished. The necessity of using a stone bottom, and 
the further necessity of cooling the fire almost every 
day to put in a new bottom, are great obstacles in 
the way of cheapness ; and frequent schemes have 
been devised to avoid them, but in vain. In those 
countries where iron or coal bottoms are used, as in 
Styria and Carinthia, the work is carried on only in 
the day-time. This certainly involves a great ex- 
pense in coal and labour, but it seems to be necessary 
and unavoidable. If the manufacture of natural 
steel could be carried on without intermission, by day 
and night, as is the operation of making iron, it cer- 
tainly would not cost any more to manufacture the 
former than the latter metal — perhaps even less. 
To the accomplishment of this end, however, there 
seem to be at present insuperable obstacles ; and we 
must trust to time and further experience to simplify 
and cheapen the process. 



GERMAN STEEL. 115 



MAKING STEEL IN A PUDDLING FURNACE. 

Some years ago we noticed a process of making 
steel in a puddling furnace ; it was made of very good 
steel-iron, puddled by dry wood. The product looked 
like steel ; but it was no more steel than strong cold- 
short iron ever will be. In the following pages we 
shall endeavour to show that any use of the puddling 
furnace in making steel is wrong in the principle ; 
good steel can never be made in that way, or by any 
such means. 



REFINING OF STEEL. 

Natural steel obtained in the way described is not 
marketable, or ready for use. Before it is exposed 
to sale, it is refined or tilted ; the bars, either flat or 
square, as they come from the forge, are sent to the 
tilt. This consists of a force-hammer, or hammers, 
of from one hundred to two hundred and fifty pounds 
in weight, and a series of forge-fires. A forge-fire 
is similar to a common blacksmith's forge, and the 
refining is done by bituminous or mineral coal. It 
is also sometimes done by charcoal ; but mineral coal 
is preferred. 



116 MANUFACTURE OF STEEL. 

The steel to be refined is broken into convenient 
lengths of twelve or fifteen inches, and piled or 
fagoted so as to make a fagot of fifty pounds. The 
bottom and top of the pile are to be in one length ; 
the interior may be composed of short pieces. A 
fagot is taken in a pair of strong basket-tongs, and 
heated in a fire to redness ; if it is found to be open, 
the red-hot pile is gently pressed together by a hand- 
hammer. When close, it is taken to another fire, 
where it receives the welding heat. Before and dur- 
ing its exposure to the welding heat, the pile is 
sprinkled over with burnt and finely-ground clay, 
partly to protect it against the blast, and partly to 
remove the dry film of scales, which are generally 
more refractory on steel than on iron. When suffi- 
ciently heated at one end, the fagot is brought to the 
hammer, and that end is welded. The tongs are now 
fastened to the welded end, which is generally drawn 
down to one and a quarter or one and a half inch 
square, and the other end of the fagot brought into 
the fire, welded, and drawn. 

If the steel is to be refined again, the bar is cut 
into two or more pieces, and again welded and drawn 
out. This process is repeated, or may be repeated, 
four or five times in succession ; and the steel is then 
called two, three, or five times refined steel. 



GERMAN STEEL. 117 



THE REFINING FIRES 

Are not different from a common smith's forge, 
except that they are larger and lower. Where char- 
coal is used, and of course where anthracite is to be 
used, the fire is provided with a long arch of fire- 
brick, of about two feet span, and one foot high 
above the tuyere. Bituminous coal, which contains 
so much bitumen as to cake, forms an arch over the 
fire by itself, and a brick arch is therefore unneces- 
sary. No injury to the steel need be apprehended 
from the use of any of the varieties of fuel we have 
named ; still, it is advisable to drive off the bitumen 
of the mineral coal before any steel is brought into 
contact with it. These fires are frequently provided 
with two or three tuyeres in a horizontal line, to 
make a continuous fire for long fagots. 

The refiner, or tilter, can accomplish a great deal 
in making the steel uniform ; but he cannot be ex- 
pected to improve a defective quality of material. 
By making the bars small and flat, and assorting 
them well, a superior article may be made of good 
raw steel. A great deal depends upon piling the 
bars and forming the fagot. The labourer who per- 
forms that work should understand the nature of the 



118 MANUFACTURE OF STEEL. 

steel by its fracture, and pile accordingly. Hard 
steel should be piled next to that which is soft, and 
inferior steel between that which is of a better qua- 
lity. Notwithstanding all the attention we give it, 
it is impossible to make a bar uniform in itself, and 
uniform with another. We not unfrequently find 
spring-steel, shear-steel, mill-steel, mint-steel, and 
other varieties, in the same bar. The bars are there- 
fore all thrown in cold water, hardened and broken, 
and, according to the fracture, assorted for market, 
where it is known under different brands, or signs, 
which are burned upon the kegs in which it is trans- 
ported. 

The steel made in this way is certainly far from 
being perfect ; but still, for the manufacture of some 
articles, it is admirably suited, and is even superior, 
for such purposes, to the best cast-steel. For 
instance, swords are made of it which cannot be 
imitated by a prime article of cast or shear-steel. 
For almost all other manufactures, however, this 
natural steel is inferior to good shear or cast-steel, 
on account of its irregularity. This irregularity has 
given rise to many attempts at improvement, and 
the steel has been re-melted, in the hope of convert- 
ing it into cast-steel ; but it is of so refractory a 
nature, that the best crucible will not melt it, at 



OEKMAN STEEL. 119 

least not to advantage. An attempt has also been 
made to use this natural steel, instead of iron, for 
cementing in the converting furnace ; but the expe- 
riment was not fully successful — the steel was found 
to be inferior, for that purpose, to good soft iron. 



120 MANUFACTURE OF STEEL. 



CHAPTER IV. 

AMERICAN AND ENGLISH METHOD OF MAKING STEEL. 
BLISTERED STEEL. 

The amount of steel annually manufactured in 
England is twenty-five thousand tons; one-half of 
the iron consumed in this manufacture is imported 
from Sweden and other parts of the continent of 
Europe, while the remainder is obtained at their own 
charcoal forges. The best steel is made .of Swedish 
Danemora iron ; but not more than twelve or fifteen 
hundred tons of this iron are imported, as its price 
ranges above one hundred and eighty dollars per ton. 
The remainder of the foreign iron used is common 
Swedish, Norwegian, Russian, German and Madras 
iron. It is generally in the form of hoops, or bars, 
of a half to five-eighths of an inch thick, and from 
two to four inches wide. We shall now proceed to 
describe the making of steel in Sheffield. 



BLISTERED STEEL. 



121 



The first operation in this branch of the manufac- 
ture is to range the iron bars in the " converting fur- 
nace." In fig. 22 is a section vertically through the 
chimney, representing the cementation boxes, fire- 
grate, and the arch over the boxes. Fig. 23 is a 

Fig. 22. 





horizontal section of the boxes and flues. In each, 
the same references show the same objects. The 
whole of the converting furnace has the appearance 
of a glasshouse. The grate, A, divides the interior 
of the furnace into two equal parts, each containing 
a cementation box. There are some furnaces which 
11 



122 MANUFACTURE OF STEEL. 

have but one box ; but they are not found so advan- 
tageous as double furnaces, owing to their greater con- 
sumption of fuel. The fire-grate, A, is over the 
whole length of the furnace ; but its breadth varies 
according to the fuel used — inferior fuel requiring a 
greater breadth than that of a better quality. The 
object here is not so much the intensity as the bulk 
of the heat ; and it is accomplished by the slow con- 
sumption of a heavy body of fuel. A grate of two 
feet in width for bituminous, and three for anthracite 
coal, may be considered as sufficient. The fire passes 
entirely around the cement-boxes, BB, and finally 
escapes at C, where a succession of draft-holes is 
left in the arch. These draft-holes are so arranged 
as to admit of being either partially or entirely shut. 
In case the heat is stronger on one end than at the 
other, it is to be regulated by pening or closing 
these flues. If the heat should be found too great 
towards the close of the operation, it may of course 
be promptly regulated in the same manner. The 
flues between the boxes are six by eighteen, and the 
others six by eight inches. The firing is done at 
both small ends of the furnace; for the grate is 
long, and cannot be conveniently reached from one 
side. At one of the smaller ends of the furnace are 
two small orifices, DD, for drawing out the proof- 



BLISTERED STEEL. 123 

bars. On the same side with the proof or tap-holes, 
which serve also as charging-doors, is the door F, 
through which the workman enters in filling and 
emptying the cementation-boxes. In many furnaces 
there are, besides the above apertures, two doors for 
the charging and discharging of the steel ; these are 
above the troughs. 

The external dimensions of the conversion furnace 
are fifteen or sixteen feet in width, by twenty-four 
feet long ; and the conical chimney is from forty to 
fifty feet high. The exterior or rough wall is built 
of common brick, or stone ; the interior, of fire-brick. 
In case the walls cannot be supported by heavy ma- 
sonry on the outside, the furnaces are to be kept 
together by wrought-iron binders. The first plan is, 
however, the best of the two. The fire-brick arch, 
or top of the interior of the furnace, is as flat as 
possible — just high enough to admit the steel-maker. 
Heavy walls and brick-work are of advantage in the 
converting operation. 



124 MANUFACTURE OF STEEL. 



THE TWO CHESTS, 

Or cementing-boxes, are in most cases twenty feet 
long each, though sometimes they are but ten or fif- 
teen feet in length. They are occasionally three feet 
high, and of the same width ; but this is a disadvan- 
tage, as it requires an unusually attentive and skilful 
workman to manage such large chests. The lower 
and smaller they are, the easier is the work, and the 
more uniform is the quality of the steel. On the 
other hand, there is a proportionately greater con- 
sumption of coal in small than in large boxes. 

The boxes are made of sandstone slabs, the joints 
of which rest upon, and are covered by, the tongues 
which form the flues. These slabs are of tabular 
sandstone, which naturally exfoliates or splits into 
thicknesses of one or two inches — the proper size 
for the slabs. These should be in one way as high 
as the intended height of the box, or as wide as the 
bottom ; the other dimension is less definite, and may 
be arranged so as to have the joints properly covered. 
The tongues which form the flues are small, and take 
as little off the heating surface as possible, merely 
sufficient to secure the permanency of the box. A 
new box is heated very gently for the first few days, 



BLISTERED STEEL. 125 

so as to produce the gradual expulsion of the water 
of the stones ; the heat should not be higher than 
the boiling-heat of water. The slabs are cemented 
together by fire-clay; in fact, the joints of the whole 
interior are so united. Small boxes are often set 
without heads ; but it is preferable to have flues on 
both ends, as well as along the sides. 

CHARGING OF THE BOXES. 

The boxes are charged with iron in the following 
manner : On the bottom of each trough is placed a 
layer of coarsely-powdered charcoal, about two inches 
thick. Upon this layer of charcoal, or cement, a 
layer of iron bars is laid edgwise, leaving a space of 
an inch at each side, and also between each bar a 
space equal to the thickness of the bar. The bars 
are to be within a couple of inches of the length of 
the box ; but in case they are too short, small pieces 
may be used to make them of the requisite length. 
Above the first layer of iron, a layer of cement is 
spread, of half or three-quarters of an inch thick, 
and upon this another layer of bars with spaces, as 
in the first layer. The spaces between the bars are 
closely filled-in with charcoal powder, or cement; 
care must be exercised to have every crevice well 
11* 



126 MANUFACTURE OF STEEL. 

filled with cement. The bars are never allowed to 
touch each other or the trough. The boxes are filled 
to within six inches of the top, and this space is filled 
with the refuse cement of former operations. Finally, 
a layer of fine sand or mud is spread over this last 
cement. The material used for this purpose in Shef- 
field consists of the sand worn off of grindstones, 
which is a mixture of particles of iron, fine quartz, 
and a little clay or lime. This is called in Sheffield 
" wheels warf," and makes a very close and compact 
cement, almost impervious to water and air. 



THE CEMENT 

Consists of ground charcoal, made from hard wood, 
sometimes mixed with soot, or of soot only. This 
charcoal powder is intimately mixed with one-eighth 
or one-tenth of its weight of wood-ashes, and a little 
common salt. Good steel is made without ashes or 
salt, by using simply charcoal powder ; but the gene- 
ral practice is to use a cement of the kind above 
described. 



BLISTERED STEEL. 127 



WORKING OF A CONVERTING FURNACE. 

When the boxes are well packed and covered, fire 
is kindled, and very gradually raised. For the first 
twenty-four hours the heat is merely sufficient to ex- 
pel the moisture in the boxes, cement, and cover. A 
rapid heat will injure the stone slabs or bricks of 
which the chests are made. The fire is gradually 
increased so as to raise the heat a little every day ; 
and at the end of six days, if it is designed to make 
spring-steel, the bars are ready to be drawn. Shear- 
steel requires eight days, and cast-steel from ten to 
twelve days, to be sufficiently cemented, or carbon- 
ized. Two days, and often a much longer time, are 
required to cool the furnace ; after which the work- 
men enter it and discharge the steel bars. Twelve 
tons of steel are generally made in a double furnace. 
In a single furnace, or where there is but one chest, 
only six or eight tons are made at a time. For 
the purpose of enabling the workmen to charge and 
discharge the chests, iron plates are laid over the 
fire-brick arches, on which they stand. 



128 MANUFACTURE OF STEEL. 



THE DEGREE OF CEMENTATION 

Is a nice point to determine, and cannot be de- 
cided by the length of time for which the iron has 
been exposed to the cementing process; practice 
must be had, and is always depended upon in w T ell- 
regulated establishments. Experience teaches us 
that steel for coach-springs requires a low degree 
of conversion ; after this comes blistered steel for 
common use ; then, shear-steel, steel for cutlery, and 
steel for files. Cast-steel requires a higher degree 
of conversion than any other. Some steel, such as 
cast-steel for bits, is frequently returned to the box 
two or three times, and is then called twice or 
thrice-converted steel. The point where to stop 
cementation is decided by the steel-maker in draw- 
ing and trying the trial-rod, or rods. The trial- 
rods are somewhat longer than the others ; they 
reach at one end through the thickness of the slabs 
of which the chest is formed, and may be drawn out 
from between the other bars by a pair of tongs. 
The bar itself may be but three or four feet long. 
The trial-holes, marked in the cuts D D, are called 
"tap-holes;" they are but a few inches wide, and are 
closed around the trial-rods by clay or wheelswharf ; 



BLISTERED STEEL. 129 

they are almost in the centre of the chest. An ex- 
perienced steel-maker uses but one trial-rod, though 
some persons think it necessary to have two or three 
bars. If a trial-rod has been once drawn, it cannot 
be returned to the box ; it is then broken, and from 
its appearance on fracture the quality of the steel is 
adjudged. The fire is cautiously kept so low, that 
the highly converted steel at the bottom of the box 
does not melt. If it happens that it does melt in the 
box, it is generally converted into cast-iron, and is 
useless for steel. The success of this converting 
operation depends, therefore, in a great measure, 
indeed almost entirely, on the knowledge and saga- 
city of the steel-maker. On his care and judgment 
the avoidance of losses mainly depends. Too much 
stress cannot be laid upon this point. 



GAIN IN WEIGHT. 

The bars in the process of conversion gain about a 
half to three-fourths of one per cent, in weight. They 
are entirely covered with blisters, whence the name 
"blistered steel" is derived. The steel is very irre- 
gular in the different layers of the box, as also in 
each bar. The fracture of a bar is very crystalline, 



130 MANUFACTURE OF STEEL. 

its colour a bright silvery white, and the tables of 
the crystals are lustrous like brilliants. The central 
crystals are always smaller than those near the sur- 
face of the bar. 



TILTING. 

Blistered steel is hardly fit for any purpose, no 
matter how simple or coarse the article made of it 
may be. Its blisters and fissures make it unfit for 
the manufacture of tools, until it is re-heated and 
tilted. The first operation of this kind of refining 
makes common steel ; the second makes shear-steel, 
and steel for cutlery. Very little steel is exposed to 
three welding-heats, as each heat adds to its tenacity 
and strength, but, if carried too far, will reduce 
some of it to iron. 

THE REFINING FIRES 

Are like a blacksmith's forge-hearth ; the fire is, 
however, of a larger size. Soft or bituminous coal 
is used for welding the bundles of steel. This coal 
is converted into a coke, and forms an arch over the 
fire, giving the appearance of a bakeoven. Neither 
charcoal nor anthracite has this effect. 



BLISTERED STEEL. 131 

The forge-fires are supplied with air by cylinder 
blast-machines, or by common bellows, placed above 
the head, and worked by a crank which is driven 
either by water or steam-power. The air is conveyed 
in copper or tin pipes to the tuyere. The blistered 
steel is cut or broken into lengths of twelve or eigh- 
teen inches, and four of such lengths are piled along 
with a fifth of double length. This longer bar is 
placed in the middle, between the others, and forms 
the handle to the pile. This pile, or fagot, is held 
together by being bound with a small steel rod. It 
is carried to the fire, and a good welding heat given 
to it. While in the fire, it is occasionally sprinkled 
with sand, to form a protecting slag against the im- 
purities of the coal. The fagot, when of a cherry- 
red heat, is carried from the fire to the tilt, and 
notched down — that is, hammered down in a rough 
manner — so as to unite the bars together, and close 
up every internal flaw and fissure. 

In the first heat, the fagot is merely welded in a 
rough manner ; after which the bindings are knocked 
off, and the pile is again re-heated. In the second 
heat, the welded bars are drawn out into a uniform 
rod of the thickness required, which is generally an 
inch or an inch and a half square, and twice or three 
times the length of the original fagot. The bars of 



132 MANUFACTURE OF STEEL. 

the first heat, which are common steel, are piled 
again to form shear-steel. Five or six of such bars 
are piled and held together by a slender band of steel, 
as before, when they are once more exposed to a 
welding heat in the first forge-fire, and welded imper- 
fectly, or soaked, to cement the bars together. This 
fagot, which also is supplied with a long bar for a 
handle, is then carried to a larger fire, in which it 
receives a thorough welding heat, and is then tilted 
at the heaviest hammer of the establishment, called 
the " shear-hammer. " In this heat a bar of two or 
two and a half inches square is drawn out ; and if 
steel of more than two heats, or "double shear," is 
required, it is cut in two, doubled, welded together, 
and drawn out again. 

Blistered steel, repeatedly re-heated and drawn 
out, assumes a very uniform, fine grain ; it loses all 
its flaws, fissures and blisters, and is by far more 
tenacious than any other steel ; it is also less affected 
by heat than cast-steel. When rendered compact by 
welding and hammering, this steel is also susceptible 
of a very fine polish, in which respect it is but little 
inferior to cast-steel. It is therefore a superior steel 
for cutlery, and unites a fine, close texture, with great 
tenacity. 

Shear-steel has not derived its name from being 



BLISTERED STEEL. 133 

particularly useful in making scissors. In days gone 
by, there were a large kind of shears in use for dress- 
ing woollen cloth ; they were formed like those in 
use for shearing sheep, being four or five feet long, 
with blades of twelve or eighteen inches in length, by 
eight to twelve inches wide. The refined blistered 
steel was particularly adapted to make the edge and 
spring of these shears. 



THE TILTS, 

Or hammers, are very much the same as those de- 
scribed in the last chapter for tilting natural steel. 
The heaviest hammer — the shear-hammer — varies 
in weight from two hundred to four hundred pounds. 
In Sheffield, the principal and cheapest mart for the 
manufacture of steel, the hammers are driven by a 
small water-wheel, upon whose prolonged axis are 
one or more iron rings, which contain the wipers, or 
cams. In the periphery of the cam-ring, or wiper 
wheel, there are from twelve to eighteen cams, which 
strike the tail of the hammer in rapid succession, by 
which the hammer-head is raised and suffered to fall 
on the steel. To increase the effect of the hammer, 
a spring is placed under its tail, so as to work the 
hammer partly by weight, and partly by recoil. 
12 



134 MANUFACTURE OF STEEL. 

Large tilts make two hundred, smaller ones four hun- 
dred, strokes per minute. The majority of the ham- 
mer frames in Sheffield are of wood, which in fact is 
the most suitable material for tilts. In some estab- 
lishments, more than one hammer is on one wheel- 
shaft. The anvils are placed upon a stone founda- 
tion, and these stones upon a grate of wood-piles. 
The surface of the anvils is almost level with the 
floor of the tilt-house, and the workman sits down in a 
fosse, or pit, with his face towards the hammer, The 
smaller rods are tilted sitting, the larger ones stand- 
ing. At the lighter tilts, the hammer-man or tilter 
sits on a swinging seat, suspended from the roof of 
the building. While thus suspended, he takes one 
end of the bundle of rods between his legs, and by 
the motion of his body gives to the rods a rapid back- 
ward and forward motion under the hammer. Each 
tilter has two boys in attendance, to furnish him 
with hot rods, and take away those which are suffi- 
ciently hammered. The rods are heated to a higher 
or lower degree, but, after the welding is done, not 
higher than a cherry-red. Small rods of good steel, 
which very soon cool after being brought upon the 
anvil, speedily become red again under the rapid 
blows of the hammer. 

Tilting is a very important process in the manu- 



BLISTERED STEEL. 



135 



facture of steel ; and none but very skilful and in- 
dustrious men will make good hands at the tilt. In 
fig. 24, as will be seen at a glance, a tilt-house is 



Fig. 24. 




represented. The faces of the hammer-head, as well 
as the anvil, are of the best cast-steel, well hardened 
and polished. Each hammer has a blast-pipe con- 
ducted to it, which ends in a nozzle, from which a 
stream of air is constantly blowing upon the anvil, to 
keep it free from dust and scales. This cleanliness 
is necessary to impart a good polish to the steel bars. 



CAST-STEEL 

Is made by melting blistered steel in crucibles. 
The converted steel is broken into convenient pieces 
for charging it in the narrowest space possible. A 
portion of carbon is always dissipated in this process ; 
therefore, the most highly carbonized bars of the blis- 



136 MANUFACTURE OF STEEL. 

tered steel are selected to be transformed into cast- 
steel. The highly converted steel is known by its 
larger crystals and brighter lustre, in a newly-made 
fracture, than in the other bars. These broken 
pieces of blistered steel are charged in crucibles made 
of the best Stourbridge fire-clay. 



THE MAKING OF CRUCIBLES, 

Or melting-pots, is an important branch in this 
department of the art. They are from eighteen to 
twenty inches high, and of a sugar-loaf shape. The 
clay is, as we have said, of the best Stourbridge, 
worked to a high degree of uniformity and smooth- 
ness. To give it this uniformity, the clay is first 
moistened with w r ater, and well puddled ; it is then 
spread on a smooth floor underneath the casting- 
house, and worked by bare feet; this requires the 
uninterrupted work of two men for six hours. In 
some establishments, the clay is mixed with finely- 
pulverized coke, or finely-ground cement of old cru- 
cibles, or a portion of black lead ; and sometimes it 
is mixed with the whole of these ingredients. Up 
to the present time, every attempt has failed to sub- 
stitute machinery for manual labour in mixing the 
clay ; it would seem that there is an efficacy in the 



BLISTERED STEEL. 



137 



Fig. 25. 




human hand, or, in this case, in the foot, which no 
machinery has been found or can be expected to 
possess. 

The crucibles are moulded 
in a cast-iron mould, as in 
fig. 25. A is a solid block 
of wood, in which the outer 
part of the iron mould, B, 
closely fits, but still so loose 
as to be easily lifted out of 
its place. This iron mould 
is well bored out on the turn- 
ing lathe, and polished. The 
core of the mould, C, is also of cast-iron, well turned. 
It has two guide-pins, one above and one below. In 
the space between the core of the mould and the 
case, a lump of clay is laid on the bottom, just suffi- 
cient to fill the space and make a crucible. When 
the proper size of a lump has been found by experi- 
ment, it is weighed, and its weight made the standard 
for future operations, thus securing uniformity in the 
crucibles. A dried and baked Sheffield crucible 
weighs from twenty-five to thirty pounds, and will 
contain forty pounds of broken steel. 

Crucible-making is the most tedious and expensive 
branch in the manufacture of cast-steel. The best 
12* 



138 MANUFACTURE OF STEEL. 

Sheffield crucibles do not last longer than three heats, 
or one day. 

The core, C, is pressed down upon the lumps of 
clay in the mould, by which they are forced upwards 
and fill the upper part of the mould. In this way, 
the lower portion of the crucible receives the neces- 
sary degree of compactness. The hole in the bottom 
of the crucible, caused by the guide-pin, is stopped 
up with clay before the vessel is taken out of the 
mould. When the core is removed, and the bottom 
hole stopped, the mould, B, is lifted out of the wood- 
en block, and reversed upon a board. If the clay is 
of the right texture and well worked, the withdrawal 
of the core and the crucible is easy enough ; but if 
the clay is a little too damp, it will adhere to the 
iron, and is with difficulty loosened. If the clay 
should be too dry, on the other hand, tho crucibles 
are very apt to crack, or to become porous. With 
the proper degree of moisture, the crucibles are easily 
removed from the mould. The adhesion of imper- 
fectly prepared clay to the mould may be prevented, 
to some extent, by rubbing the mould with coke-dust, 
or laying sheets of paper or muslin in it ; but these 
expedients are troublesome, and the necessity for 
them should be avoided. 

The crucibles, after being moulded, are placed in 



BLISTERED STEEL. 139 

drying-stoves, where they are slowly dried by a libe- 
ral access of atmospheric air, gently heated. They 
are here dried hard, but not baked. The day before 
they are intended to be used, the crucibles are set 
upon an annealing grate, made of fire-clay, where 
they are covered with the refuse coke from the air- 
furnaces ; they are here baked, if it can be called 
baking, for one day. 

THE CAST-HOUSE 

Has a great resemblance to a brass foundry. 
There are a dozen or more air-furnaces in one or two 
ranges, their tops being on a level with the under- 
mined floor of the building, as shown in fig. 26. It 
is very convenient to have the top of the furnaces 
level with the floor, as it gives the workman a better 
chance of lifting the crucible with the melted metal. 
The ash-pits are below the floor, in a subterranean 
vaulted passage, from which the grates derive a sup- 
ply of cool air, which favours the rapid combustion 
of the fuel. The crucibles are made and dried in 
these vaults. The pit of the air-furnace is a square 
cavity ; if intended but for one crucible, it is twelve 
inches square — if for two, it is twelve by eighteen 
inches. The crucibles being six inches wide at the 



140 MANUFACTURE OF STEEL. 

Fig. 26. 




top, there is a space of three inches all around. 
The depth of the fire-pit, from the top of the grate- 
bars to the floor, is twenty-four or twenty-six inches. 
The flue leading from the furnace to the stack is 
three and a half by six inches in a single, and three 
and a half by nine inches in a double furnace. The 
crucible stands on a sole-piece of two or three inches 
high ; this may be either a piece of fire-brick, a lump 
of fire-clay, or the bottom of an old crucible. The 
in-walls of the furnaces are made originally of fire- 
brick, but are repaired with mud, taken from the 
roads where a certain kind of quartz, called "ganis- 



BLISTERED STEEL. 141 

ter," is used in macadamizing. The grate-bars are 
square bars of wrought-iron, seven-eighths or one 
inch in thickness, and are loose, so as to admit of 
being pulled out if necessary. 

A very hard shingling coke is used in these fur- 
naces, broken to the size of an egg. The grate is 
supplied with air by natural draught, which is very 
strong in these furnaces, as there is an almost verti- 
cal ascent of the burnt gases. 

A crucible full of metal requires four hours for 
melting, and three heats are made in a day. The 
first operation is to put the fresh crucibles upon their 
stand, and kindle a small fire around them ; or, as is 
generally the case, to put the crucible upon its sole- 
piece in the gently heated furnace. The crucibles 
are generally taken from the annealing fire, and, 
while still warm, set in the furnace. The heat upon 
the crucible is gradually but slowly raised, by charg- 
ing more coke, until it assumes a white heat, which 
operation requires more than an hour's time. When 
the crucible is hot, and of course glazed, the furnace 
top-plate — a sort of iron trap-door — is raised, and 
a tapered sheet-iron pipe is inserted into the hot pot. 
Through this pipe the pieces of blistered steel are 
gently lowered into the bottom of the crucible. The 
pots are usually of the capacity of thirty pounds, 



142 MANUFACTURE OF STEEL, 

though a large sized pot will readily contain forty 
pounds of pieces. 

A cover made of pot-clay, which fits the crucible, 
is now laid upon it, fresh coke given to the fire, and 
the heat gradually raised to the melting point of 
steel. This operation requires from one to two hours ; 
and in the mean time the furnace is frequently open- 
ed, and fresh coke charged, so that the fuel may be 
higher than the top of the crucible. Before the steel 
is melted, the lid is removed, and a little bottle-glass, 
or pounded blast-furnace slag, is thrown in. This 
will form a vitreous cover on the surface of the melt- 
ed steel, and exclude the access and influence of 
atmospheric air, in case the cover of the crucible is 
not sufficiently tight for that purpose. A great deal 
of fresh air draws in at the furnace door, even if it 
fits well. 

After the fusion of the steel, the crucible is still 
kept standing in the fire, to fuse it perfectly, and give 
time for the interchange of atoms in the fluid mass. 
As the melting process is chiefly for the purpose of 
making a uniform grain, those portions of the steel 
which have more carbon than others, have to dispose 
of a portion of it, and thus equalize the whole mass. 
When sufficiently fused, the crucible is lifted from 
the fire to the floor, when the cover is removed, and 



BLISTERED STEEL. 143 

the scoria taken off by an iron rod, with a scraper 
attached to it. 

The tongs with which the crucible is lifted are pro- 
vided at their fire-end with arched claws, like basket 
tongs, to fit the circle of the crucible. The work- 
men, in getting ready for casting, cover their hands, 
arms and legs with coarse bagging, formed into nar- 
row sacks, which they saturate with water before 
putting on ; they are thus protected against the in- 
tense heat. When all are ready, one smelter grasps 
the pot in the furnace, and conveys it to a certain 
spot on the floor. Other hands are ready to take off 
the cover, remove the scoria, and carry the crucible 
to the mould, into which it is cast as quickly as pos- 
sible. The smelter in the meanwhile gets his furnace 
ready for the returning crucible ; for there may be 
coke on the sole-piece, and, if so, it is necessary that 
it should be removed. 

As soon as the crucible is emptied, it is returned 
to the furnace, and the fire put in a condition to 
make another heat. The operation is now somewhat 
shorter, but very much like the first. 



144 



MANUFACTURE OF STEEL. 



THE MOULD 



Is a hollow cast-iron prism, in two halves ; it is 
either a square or an octagon — the latter for round 
steel. Steel designed to be rolled in sheets, for saws, 
&c, is cast in flat moulds. The two halves of the 
mould, while casting, are held together by hooks ; 
and it is set vertically in a narrow pit, so as to pro- 
ject but little above the floor of the building. The 
mould is well polished on the inside, and, shortly be- 
fore casting, is covered with a film of oil and finely- 
ground charcoal. It is perhaps three times the weight 
of the cast, and about three feet long. The upper 
end of the mould, into which the fluid steel is poured, 
is open, and of a bell-mouthed shape. 
Fig. 27 is a section of the mould. The 
pouring of the hot steel into the mould 
requires some dexterity and skill, if we 
expect to make a sound and uniform bar. 
The liquid metal is cast down in the cen- 
tre of the hollow mould, so that none of 
it shall touch the mould before it reaches 
the bottom. There are also larger 
moulds than those we have described, which take 
more than the contents of one crucible at a time, and 



Fig. 27. 




BLISTERED STEEL. 145 

in which steel bars of two hundred pounds are fre- 
quently cast. 

When the ingots are cold, the moulds are opened, 
and the steel removed and brought to the tilt, where 
it is treated like other steel. 

Cast-steel is much harder under the tilt than any 
other steel, and, what makes it still worse, it will 
bear but a low degree of cherry-red heat before it 
becomes brittle, and falls to pieces under the hammer. 
Nor will it bear piling and welding like other steel, 
but in this respect very closely resembles cast-iron. 
Another characteristic of cast-steel is, that it is 
always more highly carburetted than other varieties, 
in order to make it fusible. Steel which contains 
but little carbon requires too high a heat to be melt- 
ed to advantage in crucibles. 

AMERICAN STEEL 

Is manufactured in a manner similar to the fore- 
going described processes. There are some slight 
variations in the converting furnaces ; but they are 
not of sufficient distinctness and importance to war- 
rant us in giving a particular description of the pro- 
cess. We shall allude to this in the next chapter. 
There is but little cast-steel at present manufactured 
13 



146 MANUFACTURE OF STEEL. 

in this country. Indeed, what has been done may be 
looked upon more in the light of experiments, of an 
undecided nature, than as a regular and systematic 
course of manufacture. The apparatus does not 
differ in any respect from that described in this chap- 
ter, as we may show hereafter. 






GENERAL REMARKS. 147 



CHAPTER V. 

GENERAL REMARKS ON MAKING STEEL. 

WOOTZ. 

To make wootz, or Damascus steel, in the United 
States, is out of the question. Even if we had the 
materials, which we certainly have not, and if we 
could pay an exorbitant price for such steel, there 
would still be no inducement for its manufacture 
among us. The steel used in the United States is 
intended for the arts of peace; and for such pur- 
poses, cast-steel, and shear or blistered steel, are all- 
sufficient. Wootz, and similar kinds of steel, are 
undoubtedly superior for instruments of war, and the 
finer descriptions of cutlery ; but these advantages 
do not make up for the expensive and tedious pro- 
cess of manufacture, and must for ever prevent its 
introduction among us. We need therefore say no 
more on the subject. 



148 MANUFACTURE OF STEEL. 



GERMAN STEEL 

Is at present not manufactured in the United 
States, and will not probably again be attempted, 
because the particular kind of ore from which the 
Germans make their cheapest and best steel has 
never yet been found in such a quantity and of such 
a quality as to warrant the erection of steel-works. 
The fact that we have no spathic carbonate of iron, 
or sparry ore, however, does not, in our opinion, fur- 
nish a good ground for excluding the manufacture of 
German steel. There are localities where it might 
be carried on successfully. There is an abundance 
of pure and rich iron ore scattered over nearly all of 
the States ; and, though every ore, even if pure, will 
not make good steel, still there are many deposites 
of rich ore which are in every way suited for the 
manufacture of natural steel. A great difficulty in 
the way of our advancement in this manufacture is 
the high price of labour, which renders us unable to 
compete with foreign manufacturers. Another diffi- 
culty is found in the fact that our operatives are 
not skilled in the manufacture. For the last thirty 
years, the aim of the iron manufacturers has been to 
increase the quantity, with, in most instances, an en- 



GENERAL REMARKS, 149 

tire disregard of quality. Now, as the first requisite 
in the manufacture of steel is a superior quality of 
iron, it is not surprising that we encounter difficulties 
in the process. As the majority of our native work- 
men may be considered as belonging to the English 
school of operatives, and as the tendency of England 
has been to make cheap iron for export, we naturally 
fall into the same practice. 

German or Swedish working cannot succeed here, 
because our material and our social relations are so 
widely different from theirs, that their mode of ope- 
rations is altogether unsuited to us. If we would 
succeed in this important branch of industry, we must 
cultivate our own resources, augment our knowledge 
of materials and the mode of working them, and 
raise a set of native hands, who shall take a proper 
interest in the successful prosecution of their art. 

FIRST ELEMENT. 

In making steel, the first and most important ele- 
ment is the iron-ore. To be sure, steel may be made 
of almost any kind of ore ; but it would be found, in 
the end, that the product would cost more than it 
would come to. Bog ore, the common impure hema- 
tites, the compact carbonates and hematites of the 
13* 



150 MANUFACTURE OF STEEL. 

coal formation, the clay ores and red iron-stones, the 
impure magnetic ores, and all our sparry ores, will 
make steel; but the steel will never be of a good 
quality, and will always be expensive. There are no 
doubt many heavy deposites of very pure and rich 
iron-ore, particularly the rich ores of Vermont, Con- 
necticut, New York, and New Jersey ; the beautiful 
hematites and pipe-ores of Pennsylvania ; and the 
rich ore-beds of Ohio, Tennessee, and Alabama ; but 
it is questionable whether natural steel can be made 
successfully even of any of these ores. They are 
adapted to make blister, shear, and cast-steel, and 
many of them will make a pure iron for conversion 
into steel ; but here their usefulness may be said to 
cease. Magnetic ore and pipe-ore, even if of the 
best quality, cannot profitably be converted into 
natural steel. 

We come now to the only ores which can with 
profit be used for the manufacture of natural steel, 
and which fortunately are found in great perfection 
and abundance. These are the ore of the Missouri 
iron-mountain, and the recently discovered deposites 
near Lake Superior. There are also fine specular 
ores in Pennsylvania and New Jersey ; but the 
amount is more limited than in the above localities, 
and the ore is not of so pure a quality. An iron-ore 



GENERAL REMARKS. 151 

to be converted into natural steel should be cheap 
and pure-— either a carbonate or a per-oxide — to be 
profitable. 

The conversion of cast-iron into steel has been be- 
fore described ; it is by no means difficult if the pig- 
iron is suitable ; but, should the iron be impure, it 
is a tedious operation. Proper attention must be 
paid, in making natural steel, to the conversion of 
the ore into crude iron. The usual method of con- 
ducting a blast-furnace will not answer in this case. 
Crude iron for steel requires a very regular and not 
too heavy blast, a wide hearth, and steep boshes, 
The charges of the blast-furnace ought to be entirely 
without lime, or at least with as little lime as possi- 
ble; and for the same reason, any ore containing 
lime is to be rejected. Hot-blast is to be avoided by 
all means ; it should never be used where good 
wr ought-iron is made, and is utterly unsuitable for 
steel. Charcoal is the best fuel for the blast-furnace ; 
it should be of pine, coarse and well charred. All 
brands and pieces of uncharred wood must be care- 
fully rejected. 

A leading object in making cast-iron for natural 
steel is to purify it of all admixtures but of carbon ; 
and for this reason particular attention must be paid 
to the operation. The ore is therefore to be pure, 



152 MANUFACTURE OF STEEL. 

clean and dry, and, if not a per-oxide, well roasted 
by charcoal or wood. Fluxes should be avoided, if 
possible ; the iron oxide or manganese itself is to be 
the flux ; the cinder is then of a brownish colour and 
glassy fracture. The hearth-stones are to be of fine- 
grained sandstone, with a liberal admixture of clay. 

Another important object in the operation is to 
flux the impurities of the ore by spending or wast- 
ing some of the iron in the ore ; for this purpose, a 
cheap ore is necessary. So long as we insist upon 
having thirty-nine out of the forty parts of iron 
which an ore may contain, there is no possibility of 
obtaining an iron which is suitable for making steel. 
We require not only a pure iron, but also an iron 
which contains carbon, if we would make good steel ; 
and to secure such iron, we have to charge a liberal 
quantity of charcoal along with the ore, being care- 
ful not to raise the heat in the furnace so high as to 
cause impurities in the iron. In short, a low heat, 
and an abundance of coal and good ore, will produce 
a superior steel ; it is idle to hope for it in any other 
way. 

Our deposites of rich pure ore are of so great an 
extent, and in such abundance, that a ton of the ma- 
terial costs a mere trifle ; and if charcoal or wood 
can be had equally low, the place for a steel-works is 



GENERAL REMARKS. 153 

indicated. Steel does not cost so much in the article 
of labour, as for materials ; where the latter are ex- 
pensive, the steel of course is so ; but where materials 
are abundant and of good quality, there is no impe- 
diment to carrying on the business successfully and 
profitably. As we have already said, the present 
mode of conducting blast-furnaces will not produce 
iron sufficiently good for conversion into steel ; and 
we have indicated the faults in the system. 



BLISTERED STEEL. 

In making blistered or cast-steel, there is little or 
no difficulty; the mechanical operations of conver- 
sion, melting and tilting, are well performed by our 
workmen, and it is unnecessary to make any further 
remarks upon them. But here, as in the case of the 
natural steel, the difficulties in the manufacture arise 
from the quality of the iron used in conversion, and 
not from any want of skill in manipulation. 

The American steel at present in the market shows 
that we have the means of making good steel, but 
that there is some deficiency in the quality of that 
produced. In Pittsburgh some very excellent spring- 
steel is made ; indeed, it is superior for springs to 



154 MANUFACTURE OF STEEL. 

any of the imported article. In Philadelphia, large 
quantities of converted steel are worked into saw- 
blades of excellent quality. All this steel, amount- 
ing to near seven thousand tons annually, is made of 
iron which is smelted from hematite and pipe-ores. 
There is frequently some iron among that to be con- 
verted which would make fine shear or cast-steel; 
but, as it is not of a uniform quality, it cannot be 
depended upon. This irregularity, which is a chief 
objection to this otherwise superior iron, is a serious 
and apparently insuperable impediment to the pro- 
gress of the steel factories. 

Cast-steel is manufactured in New Jersey, and 
also in Pittsburgh, at the present time. We know 
little of the progress of those establishments, how- 
ever, and suppose they suffer under the general com- 
plaint — imperfect iron. As it is of vital importance 
to the prosperity of steel-works to have good iron, it 
may be the better plan for us to define, first, what is 
good iron, and then show precisely how it should be 
made. 



GENERAL REMARKS. 155 



GOOD IRON FOR CONVERSION 

Is pure iron, no matter whether strong or weak. 
The strongest kind of iron is generally the least 
valuable for this purpose. Fibrous iron is usually 
inferior to short iron; but the rule is not to be im- 
plicitly relied on. Iron may be fibrous, and still be 
pure, though there is little of it known which is of 
this character. Colour, strength and hardness are 
not unerring guides in arriving at a decision as to the 
fitness of iron for making steel. Bright iron, of a 
brilliant lustre, may contain phosphorus, silicon, or 
some other matter which renders it unfit for steel. 
The strongest fibrous iron generally contains more 
silex than other pure kinds of iron ; chemically pure 
iron is also fibrous, but it is weak. Iron may be 
hard, and yet make a superior steel ; but this is not 
often the case. 

The safest method of ascertaining the quality of 
iron for conversion is by actual trial ; but this is an 
expensive experiment when the iron proves bad, as a 
single trial in a converting furnace of but one box 
requires from six to ten tons of metal. It is practi- 
cally impossible to obtain iron that is perfectly pure ; 
but the nearer we arrive at that standard, and the 



156 MANUFACTURE OF STEEL. 

less foreign admixture there is, the more suitable is 
the iron for conversion. 

A good plan for ascertaining the purity of iron is 
to submit it to chemical analysis. Iron may contain 
carbon to any extent ; but if it contain more than 
one-two-thousandth part of silex or silicon, phospho- 
rus, sulphur, calcium or lime, copper, tin, or arsenic, 
it will never make first-rate steel. The quality or 
value of the iron in this case is in an inverse ratio 
to the amount of impurities it contains. 

An analysis of wTOught-iron is not easily made, 
when the object is to find very small quantities of 
foreign substances ; it requires a skilful manipulator, 
and good apparatus and re-agents. It may not be 
improper here to refer to Professor James Booth, of 
Philadelphia, as in every way qualified to make the 
necessary tests. 

We have said that for conversion we need pure 
iron, no matter how it looks, or how weak or strong 
it may be. Such iron, however, is not so easily 
made. The first step towards success is pure, rich 
iron-ore, no matter of what kind. Magnetic ore is 
generally preferred ; but this is on account of its 
being usually richer and more free from impurities, 
and those of such a nature as to be got rid of in the 
refining process. There is no essential difference 



GENERAL REMARKS. 157 

between the ores which makes one more qualified 
than the other. The process in the blast-furnace is 
of the same nature as that described in the foregoing 
pages for making natural steel. For this purpose we 
require a pure grey or mottled pig. We may then 
sum up thus : The blast-furnace is to be charged with 
well-prepared ore, little limestone, less coal as above, 
an excess of ore, cold blast, and regular working. 



MAKING OE THE IRON EOR CONVERSION. 

Grey pig-iron of the kind we have described is 
boiled in the forge-fire; that is, it is not passed 
through a run-out fire, as is now frequently done at 
our forges. It is charged to the fire, and melted 
down a whole heat at once. This grey iron, when 
melted, is or ought to be perfectly fluid ; and by di- 
recting the blast upon it, with continual stirring, it 
is brought to boiling. It works rather slowly by this 
method ; but it is the proper way to make good iron. 
The process can be accelerated by throwing scales, 
or rich magnetic ore into the fluid iron ; but here 
speed is obtained at the expense of quality ; for, un- 
less the magnetic ore is freed of every particle of 
impurity by washing, the iron will be inferior to that 
14 



158 MANUFACTURE OF STEEL. 

produced by the slower method. Anything, no mat- 
ter what, thrown into the iron to make it work faster, 
is injurious, and seriously degrades the quality of the 
metal. 

The liquid mass is kept boiling under continual 
stirring until the iron crystallizes into lumps, which 
are brought before the tuyere, and, under the influ- 
ence of a strong heat, welded together. A large 
quantity of cinder is kept all the time in the hearth, 
which is occasionally tapped, particularly when the 
iron is about to be welded and shingled. 

It is useless to think of making good steel-iron of 
white plate-iron, or iron which does not boil. If the 
crude iron is pure and of the best kind, it still re- 
quires time, skill, and labour to reduce the amount 
of impurities to such an extent as to make good iron. 
As the purest iron is never too pure, there is no limit 
to the qualitative improvement of this description of 
iron. 

The puddling process is not so far perfected as to 
enable us by its use to make good steel-iron; our 
knowledge of the operation is entirely insufficient for 
this purpose. There is no other method at present 
known to us but the charcoal-forge, good pig-iron, 
plenty of coal, and careful and competent men to 
conduct the operations. 



GENERAL REMARKS. 159 

The description given in Chapter IV. of the appa- 
ratus and manipulation for converting and melting 
steel are sufficient for all practical purposes ; but we 
■will here allude to some leading principles which it is 
important to know. A remarkable feature in the 
nature of steel is, that it continues to be steel until 
it is melted, when it turns into white cast-iron ; and 
this is true of all the varieties of steel. A know- 
ledge of this fact is important in constructing con- 
verting furnaces ; they should be so constructed as to 
give a uniform heat over the whole interior, that one 
part of the chest might not become hotter than an- 
other. The strength of cast-steel would be no greater 
than that of white cast-iron, if it were melted in an 
apparatus where it could absorb impurities. The 
iron in the converting-box is in contact with foreign 
matters which are injurious to steel ; and if the con- 
verted iron melts in such a box, its fitness for steel is 
generally destroyed. If iron could be cemented to 
any degree we chose, it would gradually be converted 
into a fine grey cast-iron, in which form it would ab- 
sorb little or none of the cement. The combination 
takes place only when the iron is in a molten state. 



160 MANUFACTURE OF STEEL. 



THE CEMENT 

Consists principally of charcoal ; and there is suf- 
ficient evidence that pure charcoal will make the best 
steel. All descriptions of iron, however, are not 
similarly composed; and as carbon alone does not 
make the very best steel, there is a necessity for a 
compound cement. The charcoal is used in the form 
of a coarse powder, the grains of the size of blasting 
powder ; it is sifted, and the fine dust, a great deal 
of which is made in pounding the coal, is thrown 
away. Sometimes the charcoal is cut by a sharp 
knife, set in a machine similar to a straw-cutter. 
Charcoal made from the harder w T oods, such as white- 
oak and black-jack, hickory, dogwood, sugar maple, 
&c, give us the greatest quantity of cement, and of 
the best kind. The addition of refuse tobacco, such 
as is thrown away by segar manufacturers, may prove 
of advantage to the cement. An addition of ten or 
fifteen per cent, of pure lampblack is also an im- 
provement, but rather expensive. In the Western 
States, or the bituminous coal region, lampblack may 
be made cheaply ; but if not of the purest kind of 
coal, it will injure the steel. Sulphurous coal, there- 
fore, should not be used. Anthracite powder, coke 



GENERAL REMARKS. * 161 

powder, and black lead or plumbago, are inadmissi- 
ble, either pure or in admixture with charcoal. The 
cement generally in use is composed of charcoal 
mixed with one-tenth part of good wood-ashes, and 
about one-thirtieth of common salt. The whole of 
it is then moistened and well mixed. Some estab- 
lishments vary the cement slightly, but the majority 
use the proportions above given. 

For some descriptions of iron, charcoal alone 
makes the best cement. In such cases, the wood of 
the gum, poplar, sassafras, &c, which make but little 
ashes, should be charred. Charcoal made from pine 
is to be rejected, as it is too soon exhausted. Some 
metallurgists have tried and recommended the addi- 
tion of borax, prirssiate of potash, horn, bones, vine- 
gar, manganese, sal-ammonia, and a variety of other 
things ; but none of these admixtures have any be- 
neficial effect upon the steel. 

Experiments have been tried with a view of mak- 
ing steel by conducting carburetted hydrogen gas 
between bars of hot iron ; or leading carbonic oxide 
gas to it ; or cementing with diamond powder, and 
similar projects. These experiments, however, have 
all proved abortive ; bad iron cannot be converted 
into good steel, under any circumstances ; and it is 

certain that charcoal powder is at least equal to dia- 
14 * 



1Q2 MANUFACTURE OF STEEL. 

motid powder, or anything else that has been tried 
up to the present time. 

The size, form and material of the converting- 
chest has some influence on the quality of the steel 
made. For spring-steel, the boxes may be three feet 
high and three feet wide; such a box will take a 
charge thirty inches high. The chest, however, had 
better be not more than thirty inches each way ; this 
size will consume a little more fuel than the other, 
but that loss is richly made up in the superior quality 
of the product. In wide and high chests, particu- 
larly the latter, the central bars are never so well 
cemented as they should be, while the extreme bars 
absorb too much carbon. As a general rule, Ameri- 
can converting-chests are not wider than thirty inches ; 
while in Europe we frequently find them of the larger 
size mentioned. 

The length of the boxes is unlimited, except by 
the strength of the furnaces. Long boxes require to 
be well secured by iron binders; of course, with 
shorter boxes, this is not so important. In this 
country we find no boxes less than twelve feet long, 
and they do not often extend beyond twenty. The 
grate is somewhat troublesome to manage in long 
furnaces ; but this is not of much consequence. The 
size of the grate is of some importance in the result ; 



GENERAL REMARKS. 



163 



it is better in all instances to have it too large than 
too small. A grate two feet wide by thirty inches 
deep is a good size for bituminous coal, with thirty 
inch boxes. For wood or anthracite coal, the grate 
should be four feet wide. In this case the boxes 
will be rather far apart, because the bottom of each 
box is to rest on solid masonry, and there will con- 
sequently be a considerable loss of heat. To avoid 
this loss, we put another box in the open space, thus 
making three boxes in the furnace. The middle box 
is to rest upon a series of fire-brick arches, which are 
sprung upon the tongues ; and as these arches are 
higher than those tongues, the middle box will be 



Fig. 28. 




164 MANUFACTURE OF STEEL. 

higher than the other two, and the whole will assume 
the arrangement represented in fig. 28. 

The flues around the boxes are to be of uniform 
size, and so arranged as to make an equal heat all 
over the furnace. If, after the first trial, it is found 
that the boxes work hotter in one place than in an- 
other, the flues in the hottest parts are to be made 
narrower. The arch is to be as flat as possible, and 
at least nine inches thick. The spring or height of 
the arch will depend upon the resistance of the rough 
walls of the furnace ; if these are secure, and the 
furnace well provided with iron binders, the arch 
may be very flat. The flues are generally in the 
centre of the arch ; but should the furnace work hot- 
ter in the centre than on the sides, some flues may 
be opened at the sides, where it is found to work too 
cold. In some instances the boxes have no flues at 
the ends ; this is allowable where spring-steel only is 
made ; but for shear or cast steel it is an ill-advised 
economy, as the ends of the bars are always better 
cemented when the fire plays freely at the ends of 
the chests. 



GENERAL REMARKS. 165 



THE KIND OR QUALITY OF MATERIAL 

Used for chests is not only of importance so far as 
durability is concerned, but it is also of influence in 
the quality of the product. In this country, and 
also on the continent of Europe, the boxes^are made 
of fire-brick; but in England they are not unfre- 
quently made of sandstone slabs. The first consider- 
ation is the durability of the boxes, and the absence 
of fissures in the material. Pure clay is the best 
material, so far as its influence upon the quality of 
the steel is concerned ; but it is liable to cracks and 
fissures, and its expansion and contraction are too 
great to admit of durability. The addition of fire- 
sand to the clay renders the latter much more dura- 
ble ; but the steel is injured just in proportion to the 
amount of sand in the admixture. Good fire-brick 
is perhaps the best material for chests; and here 
Pittsburgh has a decided advantage in its Johnstown 
brick. A similar brick, known as the Mount Savage 
fire-brick, is obtained from Cumberland county, Ma- 
ryland. The clay for these bricks is not at present^ 
but ought to be, formed into slabs of a sufficient 
length to cover a flue, and of half the height of the 
box, and then burned. Such slabs would be very 



166 MANUFACTURE OF STEEL. 

durable, and the material is decidedly favourable to 
the quality of steel. 

Sandstone slabs of good quality may be found in 
the anthracite coal region ; but they would cost quite 
as much as fire-brick. It is possible that the Mary- 
land soapstone can be used to advantage ; but, con- 
sidering that a good fire-brick chest may last for 
many years, it is scarcely advisable to risk the expe- 
riment for the sake of the trifling saving which might 
perhaps be effected. 

In the Western States, particularly in the coal- 
fields — the only localities where steel can be made 
to advantage in the West — there is no alternative 
but to use good fire-brick, that in which clay predo- 
minates. Slabs of freestone may be had in that 
region of all sizes and compositions ; but the stones 
of the bituminous coal-fields are very liable -to break 
when heated, and never bear alternations of temper- 
ature without injury. 

The thickness of the sides of the chest is gene- 
rally two inches, which is quite sufficient; but a 
greater thickness does no other harm than that it 
requires the use of more fuel. 



GENERAL REMARKS. 167 



A NEW BOX 

Should be gently dried and heated up to its normal 
heat, and then slowly cooled, before any iron is 
charged. This is necessary to open those fissures 
"which may be invisible in the bricks or joints. At 
each heat, before any iron or cement is charged, the 
box is to be carefully examined, and the smallest 
crevice or joint cautiously filled with a fire-clay which 
is chiefly composed of finely-ground and well-burnt 
fire-brick. The most diminutive opening in a box 
may cause great loss by burning a portion of the 
iron, and rendering it unfit for steel or any other 
purpose. Care must also be taken to prevent any 
iron, such as binders, wedges, plates, &c, from com- 
ing in contact with the chest, as it injures the fire- 
brick. 



FORM OF IRON. 

It is not only the quality of iron which has influ- 
ence upon the manufacture of steel; a great deal 
depends also upon the form in which it is used. Iron 
which has become rusty from exposure to the atmo- 
sphere is to be cleaned of its oxide, and not used 



168 MANUFACTURE OF STEEL. 

until that is done. The iron bars for conversion, too 
should be as free from scales or hammer-slag as pos- 
sible ; on this account, hammered iron is preferable 
to that which has been rolled. Rust or hammer-slag 
forms a coating of very close and compact carburet 
of iron, through which the carbon cannot penetrate. 
All coarse fibrous iron, even if of good quality, should 
be rejected, as it makes imperfect steel ; the same 
may be said of iron which is unsound, splintery, and 
scaly. The size of the iron, also, is a matter of 
some importance. Swedish and German iron for 
conversion is usually of the thickness of a common 
horse-shoe or wagon-tire. In Pittsburgh, rolled bars 
of four or four and a half inches are generally used. 
In Philadelphia, we see slabs for cementation of 
about two feet long, five or six inches wide, and three- 
fourths of an inch thick. 

Bars for blistered steel, shear-steel, and all those 
kinds of steel which are not melted, but simply tilted 
or rolled, should not be thicker than half an inch, or 
even less. The difference in a thick bar, between the 
exterior and interior parts, is too great to be removed 
by simply tilting or rolling them. Bars which are 
designed for cast, spring, or coarse blistered steel, 
may be three-fourths of an inch ; but they should be 
longer exposed to the heat, and, in the case of cast- 



GENERAL REMARKS. 169 

steel, the conversion should be two or three times 
repeated. 

Shear-steel, to be profitably manufactured, requires 
thin and small bars, which need but little refining to 
be uniform. The inducements to use heavy iron are 
a saving of time and fuel. A box which will take 
seven tons of wagon-tire size will take but six tons 
of horse-shoe bars ; while at the same time it will 
contain ten tons of four inches by three-fourths of 
an inch. Very small iron is too unprofitable in the 
blistering process, even if of greater advantage in 
refining. The bars should be always at least two or 
three inches shorter than the boxes, as iron expands 
more by heat than brick, and an iron bar of twenty 
feet in length will gain two and a half inches by the 
time it is red-hot. 

There is a point also in the size of the furnace, at 
which it is found that the iron works most advan- 
tageously. Small iron and small furnaces work 
faster and more uniformly than large iron and large 
furnaces ; the only disadvantage being that they use 
more fuel. Where fuel is cheap, and where shear-steel 
is to be made, or steel refined in any form, it is more 
profitable to use small iron and small furnaces ; for it 
saves labour in tilting and re-heating. Furnaces so 
large, and iron so heavy, as to require more than ten 
15 



170 MANUFACTURE OF STEEL. 

days for conversion, are not profitable ; because the 
charcoal cement works but for a certain time in a 
certain heat, and all additional time and heat is use- 
less waste. Bars which require more carbon than 
can be given to them in a week's time, like those for 
cast-steel, had better be converted a second time with 
fresh cement. 



THE FIRING OF A FURNACE 

Is to be conducted with intelligence, particularly 
at a large establishment. Too rapid firing not only 
injures the furnace and boxes, but exhausts the ce- 
ment before the iron is sufficiently heated to absorb 
the carbon thus liberated. The cement or charcoal 
is a very bad conductor of heat ; and the heat of the 
most intense fire would scarcely reach the centre of 
the box before that of a more moderate character. 
Two or three days are required before a cherry or 
bright-red heat is given to the boxes \ and after this 
it is gradually increased to a white heat,, which is 
kept up regularly and constantly without diminution 
until the operation is finished. 

Small furnaces require four or five days and nights 
— large ones, from that to ten days. The kind of 
fuel has some influence on the time of conversion. 



GENERAL REMARKS. 171 

Anthracite appears to be the best fuel ; and bitumi- 
nous coal is superior to wood. 

A good steel-maker knows pretty nearly when a 
heat is done, if he is acquainted with his materials. 
To assist his judgment, the trial-bars are drawn when 
he thinks the process has been completed. These 
bars may be either of the whole length of the box, 
or but two or three feet long ; the iron is to be of the 
same quality as the other iron in the box. The 
breakage of the bar will of course show whether the 
whole of the metal has been converted into steel, or 
whether a core of iron is left in the centre. If the 
latter should be the case, the heat is continued until 
another trial shows a sufficiency of carbon through- 
out the bar. Spring-steel may be good enough for 
the purposes for which it is used, even if it has an 
iron core in the centre ; but the other varieties of 
steel, such as that for saw-blades, shear-steel, mill- 
steel, &c, are of but little value unless thoroughly 
cemented. Blistered steel, to be suitable for conver- 
sion into cast-steel, must have an abundant supply 
of carbon. 



172 MANUFACTURE OF STEEL, 



CLOSING OF A HEAT. 

When the conversion is sufficiently advanced, the 
furnace doors are closed, the chimney-top and the 
flues in the arch stopped up, and the furnace left to 
cool, which will require from two to five days, or half 
as long as the conversion. If the furnace is cold, or 
so far cooled as to admit of the entrance of a man, 
the doors and flues are reopened, and the workmen 
remove the converted bars. The size and form of 
the blisters on the surface show very nearly the kind 
of iron used, and the quality of the steel made from 
it. The best steel shows small blisters of uniform 
size ; coarse and imperfect iron shows both small and 
large blisters in great profusion ; a sound iron has 
but few blisters, and those of a large size ; coarse 
fibrous or puddled iron shows hardly any blisters. 
Blistered steel, on coming from the chest, if well 
converted, is very brittle ; if strong, it generally con- 
tains iron ; but there is no rule to be depended on : 
short iron makes short steel, even if imperfectly con- 
verted. The produce of a box, if designed for cast- 
steel or refining, is assorted according to the size of 
its crystals in the fracture, and laid by for either the 
one or the other purpose. 



GENERAL REMARKS. 173 



THE TILTING OF 

As described in Chapter IV., has been sufficiently 
explained, and requires no addition here. Steel for 
springs and saw-blades, if made directly from blis- 
tered steel, is rolled like sheet-iron, and not subjected 
to tilting or refining. A few remarks, however, are 
needed in reference to the chemical characteristics 
of cast-steel. 



CAST-STEEL. 

In former years, many experiments were made by 
Europeans, and in America also, to make cast-steel 
in a more simple way, with the hope of avoiding the 
converting process. It was thought that cast-steel 
could be made directly from the iron, without resort- 
ing to the use of blistered steel. These experiments, 
however, have utterly failed, and are now scarcely 
thought of. We will enumerate some of them as a 
matter of curiosity : The melting of wrought-iron to- 
gether with carbon, or lampblack ; the melting of 
protoxide of iron with lampblack ; protoxide of iron 
and grey cast-iron ; and the melting of pure wrought- 
iron. These experiments were so erroneous in prin- 
15 * 



174 MANUFACTURE OF STEEL. 

ciple, that success can hardly have been expected. 
Even if this were not so, the practical difficulties are 
so great, as to render success almost impossible. If 
too much carbon were used, the product would be 
cast-iron; if too little carbon, we should have 
wrought-iron ; and if the admixture were precisely 
correct, the burning of a part of the carbon, which 
would be almost unavoidable, would destroy or injure 
the steel. 

The inexperience of some metallurgists, inducing 
them to pronounce hard brittle wrought-iron to be 
steel, has been the cause of many errors. Some of 
these learned men insisted upon making good steel 
by melting grey and white cast-iron together, or, as 
before remarked, grey cast-iron and wrought-iron ; 
or carbon, plumbago, or diamond dust, together with 
wrought-iron. All these and numerous otherexperi- 
ments show that the nature of steel never was under- 
stood by these men. They assumed that any iron 
combined with a certain amount of carbon would 
make steel, which is not true. They did not discri- 
minate between pure and impure wrought-iron — did 
not know that most iron is too impure ever to make 
steel. How absurd to recommend the melting of 
volatile carbon and refractory wrought-iron together ! 
Even if the iron is of pure quality, it is almost im- 



GENERAL REMARKS. 175 

possible to guess the exact quantity of carbon ; and, 
further, the danger of burning the carbon before it 
comes in contact with the hot iron, as we haye said, 
is almost unavoidable. 

The expense of conversion is too small to permit 
us to think of such projects. Blistered or converted 
steel is sold at an advance of but one cent per pound 
upon the cost of iron ; and in this advance are com- 
prised the profits of the steel-burner and the mer- 
chant. Who would think of cutting wrought-iron 
into small fragments, or converting it into borings or 
filings, for the munificent profit of one cent per 
pound ! Even if this could be done, which we posi- 
tively deny, what would be the gain ? It certainly 
requires less time and fuel to melt blistered steel, 
than would be consumed in melting iron and carbon 
together. However allowable such experiments 
might be in Europe, where fuel is high and labour 
cheap, they are both unnecessary and unadvisable 
here, where fuel is abundant, and labour compara- 
tively scarce and high. 



176 MANUFACTURE OF STEEL, 



ALLOYS OF STEEL. 

Experiments which tend to form a better quality 
of the steel in the process of manufacture have also 
been made, but with little success. Alloys of steel 
and other metals have been made by melting them 
together ; but none except the alloy of steel and sil- 
ver ever came into practical use. This was composed 
of steel and one five-hundredth part of silver, and 
was for a time known as silver-steel of superior qua- 
lity. It has probably fallen into disuse, as we do not 
hear of it at the present day. Other alloys than 
those of the precious metals deteriorate the value of 
steel, and there is some doubt as to the beneficial 
effect of silver. On the whole, we may conclude 
that there is no advantage in forming any alloy of 
steel; it increases the expense, without any corre- 
sponding improvement. 

SELECTION OF THE CONVERTED BARS. 

In making cast-steel, the most important object is 
the selection of the converted bars. The fragments 
of steel to be charged and melted together in the 
crucible are to be uniformly and highly cemented, 



GENERAL REMARKS. 177 

and free from any iron cores. Not only is a highly 
finished cementation necessary, but all the blistered 
fragments should be of the same iron, and of the 
same heat of conversion. For cast-steel, the most 
highly cemented bars or parts of bars are selected, so 
as to have some excess of carbon, because a portion 
of it is lost in melting. The uniform grain, and con- 
sequently uniform hardness, of good cast-steel is en- 
tirely dependent upon a proper selection of the blis- 
tered steel which is subjected to the melting process. 
The throwing together of heterogeneous fragments 
of steel is often the cause of imperfect results. 
German or natural steel, or blistered steel made of 
imperfect iron, is never suitable to make good and 
uniform cast-steel. A perfectly fluid state of the 
steel in the crucible is absolutely necessary, and this 
is to be further assisted by stirring the liquid mass 
repeatedly before casting. This is done with a rod 
of good iron ; impure or puddled iron is inadmissible 
for this purpose. The melting of the steel is expe- 
dited by selecting the most highly cemented bars, or 
subjecting the bars to be melted to two or three con- 
versions. Such steel will not be injured by losing a 
little carbon, and this in burning will raise the heat 
in the crucible. Where there is sufficient carbon, 
some pure black manganese is laid in the bottom of 



178 MANUFACTURE OF STEEL. 

the crucible. The manganese, in being reduced to 
protoxide, combines with such silex and alumina as 
may be freed from the iron, and forms a slag which 
strongly resists the tendency of the carbon to decom- 
pose. The oxygen liberated from the manganese 
serves to increase the heat in the pot. Nothing but 
pure black manganese is admissible; any foreign 
matter will injure the steel. The manganese should 
be subjected to a careful chemical analysis before it 
is employed. 

THE FORM OF THE AIR FURNACES 

For melting steel has been already described; 
they are much better adapted to the purpose than 
those of any other form. A sort of reverberatory 
furnace has been proposed and tried ; but it has not 
been found of much advantage. The square form is 
decidedly in advance of the round form of the fire- 
pit. In the Eastern and Middle States, anthracite 
is the best fuel for these furnaces, and is successfully 
employed in Jersey City, in the steel-works of the 
Adirondac Company. In the Western States, coke 
is used ; and its excellence depends upon the hard- 
ness and purity of the coke. The fuel should be dry 
and warm before it is used, as, if not so, the pots 



GENERAL REMARKS. 179 

are in danger of breaking. Charcoal is a very good 
fuel, but it is entirely too expensive. There is not 
much profit or economy in double furnaces, or fur- 
naces having two pots. 



POTS. 

Of the material of which pots are composed, and 
of the manner of making them, we have spoken else- 
where ; we will therefore make but a few additional 
remarks on their form and composition. 

It has been said that a mixture of plumbago and 
clay forms the best material for the construction of 
these pots ; but in practice we do not find this to be 
the case. Pounded coke, anthracite or charcoal, are 
also added; but with little advantage. The best 
crucibles, on many accounts, are those made of pure 
fire-clay ; and the only objection to them is that they 
are liable to breakage, from their inability to resist 
a sudden change of heat. The addition of old pot- 
sand and a little coke-dust diminishes the brittleness, 
and is therefore of great advantage. Instead of 
coke-powder, the powder of burned or charred an- 
thracite — such as has passed through a blast-fur- 
nace, or the heat of a re-heating furnace in a rolling 
mill- — may with a good effect be substituted for com- 



180 MANUFACTURE OF STEEL. 

mon coke-dust. These ingredients should be perfectly 
mixed, and subjected to strong pressure in the pot- 
press. 

A saving in fuel may be effected by making the 
pots of a conical form ; but, on the other hand, they 
do not last so well if too much tapered, and the qua- 
lity of the steel is also injured. The cylindrical form 
is the best for quality and durability ; but these are 
obtained at a greater expense of fuel. Pots are ge- 
nerally of three and a half to four inches diameter 
at the bottom, and from four and a half to five inches 
at the top ; the height varies from twelve to sixteen 
inches. It is not advisable to melt more than fifty 
pounds in one crucible at a time ; the usual charge is 
but thirty or forty pounds. 

FLUX. 

The flux used to cover the melted steel, and pro- 
tect it against the air and flame of the furnace, is 
glass-powder. It is not indifferent what kind of 
glass this powder is made of; glass which contains 
much iron, lead, arsenic, manganese, or, in fact, any 
metallic oxides, will not answer for the purpose, and 
should be carefully avoided. So also of crystal, 
crown, and coloured glass. What we require is a 



GENERAL REMARKS. 181 

hard, strong, soda glass, such as is generally used for 
good window-panes ; it is white when in thin sheets, 
but assumes a light-green appearance as it increases 
in thickness. 

A flux is not absolutely necessary if the pot-covers 
fit well ; indeed, if good glass cannot be had, it is 
better to use none at all. Any other flux, such as 
potash, soda, or glass compositions, must be scrupu- 
lously avoided; they are all positively injurious to 
the steel. We have said enough to show the import- 
ance of providing good pot-covers. 

How long a pot should be exposed to heat, is not 
very easy to say. If the steel is not very fluid, it 
may require five or six hours before the operation 
can be completed ; and if so, the steel will not be 
good. In Sheffield, from three to four and* a half 
hours is considered sufficient. Steel which melts in 
less than three hours is brittle, and not strong. A 
perfectly limpid, and not a slimy, pasty state of the 
liquid steel, is necessary, and should continue at least 
a quarter or half an hour, under repeated stirring. 
The mould after casting is covered with fine sand or 
clay, to protect the hot steel from the air. 



16 



182 MANUFACTURE OF STEEL. 



TILTING OF STEEL 

Is one of the most important operations in the 
manufacture. Good tilting improves the steel, while 
imperfect work degrades it. Experience is the only 
safe guide here. The force-hammers should strike in 
rapid succession, even if the blow is slight. The de- 
gree of heat in the bars varies according to the qua- 
lity of the steel ; cast-steel bears the least, and natu- 
ral steel the highest heat. Too hot or too cold tilting 
makes the steel brittle. 



NATURE OF STEEL. 183 



CHAPTER VI. 

NATURE OF STEEL. 
HARDNES S. 

When heated to redness and suddenly plunged 
into cold water, or suddenly cooled in any other way, 
steel becomes hard — so hard, if of good quality, as 
to scratch glass. The degree of hardness depends 
not only on the quality of the steel, but also on the 
degree of heat to which it has been exposed, the me- 
dium in which it is cooled, and the manner in which 
that cooling is performed. 



FINE CAST-STEEL 

Is susceptible of a high degree of hardness, almost 
equal to that of the diamond ; but it is then too brit- 
tle to be of practical use. Shear-steel is less hard, 



184 MANUFACTURE OF STEEL. 

if hardened in the same manner as cast-steel, and is 
still more brittle. Spring-steel is not capable of so 
great a degree of hardness as either of the above 
varieties, and, if manufactured from hot-blast or 
impure iron, is very brittle. 



GERMAN STEEL 

Is frequently found to be very hard and tenacious, 
equal to good cast-steel ; but the quality of German 
steel is so irregular, that no dependence can be placed 
upon it. We frequently find very hard and tena- 
cious steel, and very soft and brittle steel, in the 
same bar of but a few feet long. We often also find 
fibrous iron and good steel in the same fracture of a 
bar. The hardest iron or steel known is the white 
cast-iron or steel-iron of Germany, of which German 
s steel is made. It is, however, so brittle when hard- 
ened, that it will not serve for any practical purpose. 
Some kinds of wrought-iron may also be hardened, 
but the metal is never sufficiently tenacious to assume 
a fine edge ; for the edges formed of it are so brittle 
as to break when exposed to slight pressure. 

The hardness as well as the nature of steel are 
greatly affected by exposure to too much or too little 
heat. A dark cherry-red heat is sufficient to give to 



NATURE OF STEEL. 185 

the best kinds of cast-steel their greatest degree of 
hardness. Shear-steel will bear a higher heat than 
cast-steel, and German steel will bear almost the 
welding heat of iron- — at least a bright white heat — 
without injury. Every kind of steel has a certain 
degree of heat by which it assumes the hardest as 
well as the most tenacious form. If heated beyond 
that point, the thin steel cracks, and the heavier 
pieces fly, either in the cooling operation, or after 
the termination of that process. If cast-steel is 
heated to whiteness and cooled, it loses its peculiar 
hardness and tenacity, becomes brittle, and can never 
be restored to its original quality. German and 
shear-steel, if the latter is well refined, can bear con- 
siderable heat without much deterioration in quality. 
Blistered steel is more sensitive to heat than any 
other variety, and for this reason is not suitable for 
welding to iron, or making miners' tools of, though 
it is frequently applied to those uses. Blistered 
steel will not admit of such frequent hardening as 
other steel. If it has been injured by too frequent 
heating and hardening, it may be somewhat improved 
by forging with quickly repeated blows of light ham- 
mers, and gentle heating. If open cracks from hard- 
ening are in the steel, a slight welding heat is to be 
given in addition. 
16* 



186 MANUFACTURE OF STEEL. 

The more steel has been forged, and the higher 
the heat it has been exposed to in manufacturing, the 
more work and higher heat will it bear in the subse- 
quent operations. It never assumes the high degree 
of tenacity that marks cast-steel, however, even if it 
should become as hard as the latter. Cast-steel is 
the hardest and most reliable steel, if cautiously 
heated. If steel is heated below its normal heat, 
and cooled suddenly, it does not assume its natural 
hardness. German steel, heated to a cherry-red, 
remains as soft as it was in its tempered state. This 
degree of heat is variable, as remarked above ; but if 
the hardening heat is not carried to the proper point, 
the hardness of the steel is always less than its qua- 
lity would lead us to expect ; in most cases, it is as 
soft as if tempered. 



THE REFRIGERATION OF STEEL, 

For the purpose of hardening it, is performed in 
most cases by simply heating it, and plunging it sud- 
denly in cold water. This process is frequently va- 
ried by moving the hot steel rapidly in the water, or 
by violently disturbing the water. The rationale of 
this process is the difference of temperature between 
the hot steel and the cooling medium, as also the 



NATURE OF STEEL. 187 

time in which it is performed. If the steel is hotter 
and the water colder, the steel will assume a higher 
degree of hardness, or become brittle. By the same 
degree of heat in the steel, water with ice or snow in 
it will make the steel harder than water of 70° or 
100°, which is generally used in the blacksmith's 
shop. To increase the hardness of steel, without 
being obliged to expose it to an injuriously high heat, 
it may be plunged into mercury, which gives it a 
high degree of hardness, because it cools more ra- 
pidly. After quicksilver, follow a solution of salt, or 
w r ater slightly acidulated by sulphuric or other acid. 
Spring or hard water imparts more hardness than 
river or rain-water. Oil and fat leave the steel softer 
than rain-water; and cooling in sand, or between 
cold iron, as in the jaws of a vice, or cooling in air, 
either in motion or at rest, have all been tried, and 
impart a greater or les-s degree of hardness, accord- 
ing to the order of their enumeration. Steel heated 
to its highest point, and plunged in the coldest me- 
dium, becomes what is called glass-hard ; that is, it 
will scratch glass ; but it is usually very brittle. 

Not only the cooling medium, and the heat of the 
steel, but the manner in which the refrigeration is 
performed, have influence upon the hardness and 
tenacity of the steel. If hot steel is thrown to the 



188 MANUFACTURE OF STEEL. 

bottom of a vessel of cold water, it does not assume 
a high degree of hardness ; but if a rapid motion is 
given to it, it speedily becomes hard, and the hard- 
ness increases with the rapidity of the motion. Large 
pieces of steel, which have to acquire a high degree 
of hardness, are refrigerated under a rapid current 
of water, which falls upon it from a certain height. 
The best swords at present manufactured are hard- 
ened by giving them a rapid motion in the atmo- 
sphere. Several kinds of saws, and other articles 
of steel, are hardened by simply hammering them. 
Engravers' tools, if made of good steel, assume the 
finest edge or point by being hammered with quickly 
repeated strokes of a very small hammer, upon the 
edge which is to form the cutting point. 

TEMPERING. 

The fact that each variety of steel requires a dif- 
ferent degree of heat for hardening it, and the diffi- 
culty of estimating that heat, because there is no way 
of measuring it, has given rise to the operation of 
tempering. The steel is therefore heated to the high- 
est degree which it can bear without being perma- 
nently injured, and is then cooled so as to impart to 
it the greatest hardness. It is then ground or pol- 



NATURE OF STEEL. 189 

ished so as to show a bright surface, and gently re- 
heated until the bright surface shows a certain colour. 
The colours produced by the increasing heat on the 
bright surface are, in succession, yellow, brown, pur- 
ple, light-blue, dark-blue, and black. These shades 
are used for the following purposes : yellow for 
lancets, razors, penknives, cold-chisels, and miners' 
tools; brown for scissors, chisels, axes, carpenters' 
tools, and pocket-knives; purple for table-knives, 
saws, swords, gun-locks, drill-bits and bore-bits for 
iron and metals ; and blue for springs, small swords, 
&c. Articles which are to be softer are made still 
darker; but when the black shade is reached, the 
steel is annealed and soft. These colours are the 
result of oxidation. The increasing thickness of the 
film of oxide which accumulates on the bright surface 
of the steel is less and less transparent as the heat 
increases. The character or composition of the oxide 
is in all cases the same. 

In a blacksmith's shop, the tempering is generally 
done by heating the object, if a chisel or pickaxe, 
from the heavy part towards the edge ; and when the 
heat moves towards the edge, and has imparted the 
desired colour, the instrument is suddenly plunged 
into cold water, to arrest further tempering. The 
thick part is thus not only tempered, but annealed, 



190 MANUFACTURE OF STEEL. 

because it is heated beyond tempering. This mode 
of tempering tools is practical, and based on correct 
principles ; but it requires care on the part of the 
blacksmith that he does not go beyond the colour 
which he intends to impart. The degree of hardness 
is tested by scratching the article with a file ; but the 
test is uncertain, and shows merely if the hardening 
is too soft, but not if it is too hard. 

Sometimes the tempering is performed by covering 
the steel with a film of oil or fat, and heating the 
steel until this oil or fat is inflamed. This is a very 
imperfect method, and cannot be depended upon ; it 
generally makes the steel too soft. Small objects 
are very well tempered by putting the steel between 
the jaws of the fire-end of a pair of blacksmith's 
tongs, which are heated beyond the tempering point. 
As soon as the steel shows the desired colour, it is 
dropped in cold water. This is perhaps one of the 
most successful methods of tempering steel. 

A somewhat scientific, but at present not much 
practised mode of tempering, is to heat the glass- 
hard steel in a bath of fusible metal, kept at a cer- 
tain heat, the objects being laid on an iron plate. 
This way is best adapted. to temper knife-blades and 
saw-blades in masses ; but we should hesitate to re- 
commend it for general use. 



NATURE OF STEEL. 191 



CHARACTERISTICS OF STEEL. 

The signs by which to distinguish good from had 
steel are very difficult to describe ; however, we shall 
endeavour to do so. If there is an opportunity of 
forging some of the steel, it is advisable to do so ; 
for there is no better means of ascertaining its true 
nature. A bar is gently heated to cherry-red, and 
drawn out into a gradually tapering square point. 
The operative who performs this labour, if familiar 
with working in steel, will judge of the quality from 
the manner in which it forges. If it is cast-steel, it 
forges harder than any other ; after this follows good 
German steel, then shear-steel, and at last blistered 
steel. Hard wrought-iron is the softest. If the trial 
is performed, and cannot be depended upon for want 
of experience, the forged point is heated to cherry- 
red, and cooled in cold water; if possible, ice or 
snow-water. After this hardening it is tried by a 
file, and, if it should be found to be soft, it may be 
concluded that it is either iron or German steel. It 
is then heated again to a higher degree of heat, and 
hardened; if it is not hard after this heat, which 
may be a white heat, it is iron. In either case, the 
steel is to have a uniform heat ; for the thin point 



192 MANUFACTURE OF STEEL. 

will naturally be hotter than the thicker portions. 
The hardened point is then screwed between the jaws 
of a vice, and just enough broken off to show the 
fracture. The power used in breaking forms the 
rule by which to judge of the tenacity of the steel 
under trial. The broken point may be tried by 
crushing it under the face of a hardened hammer, 
when laid upon a dull but hard file. If the steel is 
good, it will resist the crushing, and will cut the 
hammer-face and the file. The degree of resistance 
of this grain of steel to the crushing power is the 
best rule by which to judge of it ; for many kinds of 
steel feel hard to the file, and even cut glass, or other 
hardened steel, and yet show no tenacity. Here we 
find the true criterion of good cast-steel, and natural 
or German steel. The latter may be as hard as the 
first, but is never as tenacious when glass-hard. As 
tenacity in steel is of greater importance than hard- 
ness, it is an object to attend to this trial most care- 
fully. Hard iron will be found to be easily ground 
to dust in the experiment. Some kinds of steel, par- 
ticularly those which have been forged a great deal, 
or which never had much carbon, or in which other 
matters predominate over carbon, will not bear to be 
drawn into fine points. It may be quite strong when 
in large pieces, or even tenacious ; but still it will 



NATURE OF STEEL. 193 

that is not sufficient. Steel which is really goodwill 
take a fine point, and be tenacious if not tempered, 
unless it has been overheated. If the steel will not 
take a point, it of course will not receive an edge, 
and i3 therefore useless for any of the finer articles 
of manufacture. The white crude steel-iron of the 
Germans is harder in a body than the hardest cast- 
steel, or the hardest German steel ; but it will not 
take a strong point, nor receive a fine, smooth edge. 

The marks by which to know good steel, by sight, 
sound, or strength, are fallacious, and cannot be de- 
pended upon unless assisted by long experience ; and 
even then the result is always uncertain. The fresh 
fracture of steel is of a silver-grey colour, inclining 
in many instances to white, particularly in shear and 
German steel. Certain kinds of cold-short wrought- 
iron have a similar appearance and bright fracture ; 
but they are far from being steel. 

Hardened, refined, or much-forged steel is always 
more bright in its fracture than cast, annealed, or 
tempered steel. The lustre of a fresh fracture in 
steel, however, is as uncertain as its colour. Phos- 
phorus and silicon have the property of imparting a 
rich lustre to iron as well as steel, and hence the dif- 
ficulty of distinguishing steel by this test. Hard- 
ened steel has more lustre than that which is tern- 
17 



194 MANUFACTURE OF STEEL. 

pered, and hammered steel more than that which is 
annealed. Cast-steel not hardened frequently shows 
a fracture similar to that of fine-grained cast-iron. 
Baltimore pig-iron has more the appearance of good 
cast-steel in its fracture, than many kinds of shear 
and natural steel. 



TEXTURE. 

The most characteristic feature of steel is its tex- 
ture, or grain. The grain of good steel, when hard- 
ened or soft, is uniformly round when viewed through 
the microscope ; no flickering of light, as if broken 
by the planes of small crystals, is visible. The frac- 
ture shows a velvety uniformity, of a more or less 
white colour, and of more or less lustre ; but always 
of great regularity and uniformity ; no spots which 
are more bright or more dull than others. 

Good steel does not look like mottled cast-iron, or 
cold-short bar-iron. The fracture of good steel has 
the appearance of deadened silver ; it is of a uniform 
colour, grain and lustre, with the entire absence of 
sparkling particles. 



NATURE OF STEEL. 195 



SOUND 

Is a characteristic of steel. A well-forged and 
polished rod of sound steel, when suspended by one 
end and struck by any hard substance, emits a sono- 
rous, silvery tone. Iron does not possess this sound ; 
fibrous iron gives out a dull, unpleasant sound ; cold- 
short iron is more sonorous, but still there is no com- 
parison between it and the silvery tone of a well- 
forged bar of steel. Hardened steel is less distinct 
in this quality ; and tempered steel emits but a dull, 
shingling sound, like a broken bell, or cracked porce- 
lain. German steel, as brought into market, is also 
inferior, because all this steel is chilled before being 
packed; it is, however, in all instances, inferior in 
sound to cast-steel. 



COHESION 

Is one of the most characteristic qualities and the 
greatest merit of good steel. The absolute cohesion 
of good steel is twice as great as that of the best bar- 
iron, or 120,000 pounds to the square inch ; of good 
cast-steel, even 150,000 pounds. We refer to an- 
nealed and forged or tempered steel. Glass-hardened 



196 MANUFACTURE OF STEEL. 

steel bears less weight than forged steel; but the 
hardened and tempered steel bears still more. Steel 
which, when glass-hardened, bears but 100,000 
pounds, will, if tempered, bear 130 or 150,000. 
Good cast-steel is here again preferable to any other. 
What has been said of the absolute cohesion of steel 
may also be said of its relative cohesion ; it is far 
superior in this respect to either wrought or cast-iron. 

ELASTICITY. 

The most remarkable quality of steel is its elasti- 
city ; it is in this respect superior to any other ma- 
terial, India rubber not excepted. A good spring, 
made of good steel, will last for centuries, in constant 
use, without losing its flexibility. A good Damascus 
blade will bear any amount of bending, without de- 
viating the smallest fraction from its original form, 
when the bending force is relaxed. Good cast-steel, 
well worked, will do the same ; but its curvature is 
more limited, and it is more brittle, than Damascus 
steel. A clock or watch-spring, being always on the 
extreme of flexure, will last for years, or even cen- 
turies, without being deteriorated to an appreciable 
extent. 



NATURE OP STEEL. 197 

SPECIFIC GRAVITY. 

The specific gravity of steel is between 7.5 and 
7.9, according to quality and treatment. Hardened 
is not so heavy as tempered steel; well-forged steel 
is the heaviest. Very much in this respect depends 
upon the quality of the steel. The best qualities are 
most subject to these expansions and contractions by 
hardening. 

The mode of working steel, also, has an influence 
upon this fluctuation. If steel is made too hot, or the 
difference between the heat of the steel and the me- 
dium of refrigeration is too great, for a certain kind 
of steel, it will expand a great deal in hardening ; 
but, if hardened by the proper heat, its expansion 
will be quite small. 

FUSIBILITY OF STEEL. 

The heat by which steel fuses is very variable ; but 
all kinds of steel melt at a practicable heat. The 
finest cast-steel melts at a lower heat than any other 
steel, and the German spring-steel requires the high- 
est heat — too high a heat for the be-st crucibles. 
We may assume that cast-steel melts at 2700°, blis- 
tered and shear-steel rather higher, and natural steel 
at 3500°. 
17* 



198 MANUFACTURE OF STEEL. 



THE WELDING PROPERTIES 

Of steel are in many respects very decided, but 
vary in the degree of heat. The heat which is re- 
quired to weld German steel, to itself or to iron, is 
sufficient to convert cast-steel into cast-iron. The 
welding of two pieces of cast-steel is a matter of some 
difficulty ; but it may be welded to iron, by the help 
of a little borax, which is sprinkled on the joining 
surfaces to remove scales of oxide. Spring or shear- 
steel, and natural steel, may be welded to themselves, 
or one to the other, or to iron, just as we choose. 
The heat applied in these cases is to be given with 
caution, to avoid the burning of the carbon ; for that 
would injure the quality of the steel. Sand or dry 
clay should be sprinkled over the hot steel, to pro- 
tect it against the direct attacks of the blast. When 
iron and steel are to be welded together, the iron is 
always nearest the intense heat or blast ; the steel is 
held in the more subdued fire. If steel is heated too 
often or too intensely, it is transformed into iron, and 
frequently bad iron. Forging delays, but cannot 
prevent this result. 



NATURE OF STEEL. 199 



MAGNETISM 



Is more tenaciously retained by steel than by iron. 
The latter absorbs it most quickly, but does not re- 
tain it well ; the former absorbs it slowly, but retains 
it for years. The finest steel is more qualified to 
retain magnetism than any other; and steel of a 
dark-blue colour is superior to glass-hardened or ham- 
mered steel. The most uniform steel in hardness, 
texture, tenacity, and fineness of grain, is the best 
for magnetic instruments ; and cast-steel is of course 
to be preferred to any other. 



APPENDIX. 



In our last chapter we have enumerated the various 
qualities of steel, and their characteristics, in a con- 
cise form, to bring the subject properly before our 
readers. We shall now proceed to take a philosophi- 
cal view of the matter. 

Steel is certainly iron ; but it has less impurities 
or foreign admixtures than cast-iron, with more car- 
bon and less of other impurities than most kinds of 
wrought-iron. We cannot say that steel is simply a 
carburet of iron ; that is not true ; for it contains, 
besides iron and carbon, many other ingredients. 
Steel, as it improves in quality, gradually increases 
the number of its component parts. These, at first 
sight apparent impurities, belong to its nature, and 
constitute, in proper connection with iron, the cha- 
racter of the steel. The best and finest steel, such 
as first-rate cast-steel, contains the largest quantity 

(200) 



APPENDIX. 201 

of alloyed admixtures ; these make the steel fusible, 
but at the same time impair its capacity to resist the 
action of heat without melting. Such steel cannot 
be welded to itself, or but with difficulty, and falls to 
pieces like cast-iron when Struck by a hammer in a 
temperature at or beyond cherry-red. Blistered, 
shear, spring, and file-steel, and similar kinds, con- 
tain fewer impurities than cast-steel. But these de- 
scriptions of steel melt with great difficulty in a cru- 
cible, and are never so tenacious, fine-grained, and 
durable as cast-steel. German, Damascus, and simi- 
lar qualities of steel contain a still smaller amount 
of foreign matter ; they have body, and resist fire as 
well as wrought-iron ; but they have not the fineness 
of cast-steel. They are not, therefore, so capable 
of receiving a fine edge ; nor are they so tenacious 
as cast-steel. 

If steel is, according to this, an impure iron, and 
a very impure iron, too, we are not to conclude that 
any impure iron will make steel, or that impure iron 
ought to make good steel. It is neither the amount 
nor the quality of foreign matter combined with iron 
which converts it into steel ; " it is the form in which 
foreign matter is combined with iron, which consti- 
tutes steel." Every atom of the constitutional ele- 
ments of steel is to be combined with its fellow atom, 



202 MANUFACTURE OF STEEL. 

so as to form a well organized atom of steel — not to 
form an atom of iron, then an atom of iron and car- 
bon, and then a third atom of iron, carbon and sili- 
con, or other matter ; and these incongruous atoms 
grouped together in an irregular form. An atom of 
iron, which is alone, and is not combined with its 
ratio of other matter, is soft — is of another nature 
than its neighbour atom, which is combined with such 
elements as impart hardness to the combination. 
All the alloys are more hard than the elements of 
which they are composed; and so it is with the 
alloys of iron. Pure iron is very refractory; this 
causes the difficulty of fusing it as perfectly as other 
alloys, and it is therefore less uniform. Hence steel 
of impure iron is apt to be brittle or tender, and will not 
take a fine edge. Iron, such as cast-iron — and, in 
fact, any other alloy — if it contains too much of 
alloyed matter, is brittle. If it contains too much 
carbon, as in crude steel, it is very brittle. If sili- 
con, phosphorus, and other matter predominate, we 
always see brittle iron. Where the elements of com- 
position are well balanced, we generally find the iron 
tough, soft, and of good quality. Scotch pig-iron is 
one of the most impure kinds of iron manufactured 
in the world; still, it has qualities which make it 
superior to any other iron as a foundry metal. Iron 



APPENDIX. 203 

smelted of some kinds of bog-ore, and by charcoal, 
frequently contains but one or two per cent, of phos- 
phorus and carbon, and still is so brittle as to be use- 
less for any purpose save shot. If to such brittle iron 
we add sulphur, copper, calcium, or similar matter, it 
improves in strength and utility. These are the rea- 
sons why a composition of various kinds of ore, melt- 
ed together, make a stronger iron than a majority of 
the ores, melted singly, would indicate. The same 
reasons explain why the quality and strength of 
wrought-iron is greater when compounded, in refining 
it, of various kinds of pig-iron. The composition is 
in all instances stronger th&n the average sum of 
strength of each kind of iron refined by itself. 

Steel is iron alloyed with other matter ; and no- 
thing can impart a more correct idea of the nature 
of steel, than the nature of alloys generally. These 
always fuse at less than the mean temperature of the 
fusing heat of the metals separately. Thus, pure 
iron is infusible ; but an alloy of ninety parts of iron 
and ten of gold is almost as fusible as gold itself. 
Pure iron, we repeat, is infusible, and carbon is infu- 
sible ; but when alloyed, they melt readily at a prac- 
ticable heat. Silicon is infusible ; but when com- 
bined with pure iron and carbon, the mass melts very 
readily. Five parts of lead, three of tin, and eight 



204 MANUFACTURE OF STEEL, 

of bismuth, melted together, dissolve in boiling water ; 
while the mean degree of the melting heat of the 
component parts is 514°, or nearly a cherry-red heat. 
Almost all the alloys are malleable when cold, but 
brittle when hot ; there are but few exceptions to this 
rule. This quality of the alloys is very distinct in 
bronze, but still more in cast-iron. There are some 
kinds of anthracite pig-iron which are very tenacious 
when cold, but which, in a cherry-red heat, cannot 
bear their own weight. There is a charcoal cast-iron 
used in Pittsburgh, of which turnings ten feet long 
may be cut, but which, at a cherry-red heat, drops to 
pieces by its own weight. If such iron is freed of 
the greater part of its alloyed matter, or if it is con- 
verted into wrought-iron, it is as tenacious when 
almost at the welding heat, as when cold. 

Many alloys consist of definite equivalents of the 
single or component parts ; and it may be assumed 
that a definite relation between metals exists in all 
instances, the same as the law of equivalents through- 
out chemistry and nature. It appears that peculiar 
properties belong to the rational compounds, which 
are not so definitely expressed in the accidental com- 
position. 

The l&w of combination of different metals is ex- 
emplified and has been observed in a number of cases. 



APPENDIX. 205 

Brass composed of definite equivalents, atom of cop- 
per to atom of zinc, when alloyed, is a far superior 
metal to that kind of brass which is not compounded 
according to this law. There are at present but very 
few instances of definite compounds investigated ; 
but it is in all cases strongly indicated that a rational 
compound is natural in all instances. 



THE HARDNESS 

Of alloys is generally greater than that of their 
component parts. A slight admixture of soft tin, 
say ten per cent., renders copper very hard and tena- 
cious. If the amount is more than one atom of tin 
to one atom of copper, the alloy of these two of the 
most malleable metals is so brittle as to have hardly 
any cohesion. One atom of tin to one of copper is 
the metal of which Lord Rosse's specula are made ; 
it is as hard as steel, and has so much cohesion as to 
bear working, turning, and polishing. Sixty parts 
of iron and forty of chromium form a composition as 
hard as diamond, though the metals separately are 
not hard. 

A high degree of hardness may be imparted 
to iron and steel by the admixture of one-fourth of 
18 



206 MANUFACTURE OF STEEL. 

one per cent, of silver. Copper may be hardened 
externally by the fumes of zinc and of tin. Carbon 
and phosphorus have the same hardening effect upon 
soft iron. 



THE TENACITY, MALLEABILITY AND DUCTILITY 

Of the single metals is generally impaired in their 
alloys ; the same is the case with iron and its alloys. 
More information on this subject may be derived 
from the "Encyclopaedia of Chemistry," by James 
C. Booth; articles, " Alloy" and "Affinity." 

An opinion expressed by eminent metallurgists on 
the nature of steel, namely, the hypothesis that the 
carbon in tempered steel is a mechanical admixture, 
while in crude white iron or hardened steel it is a 
chemical combination, is a doctrine to which ive can- 
not agree at the present time. It has been proved 
that silicon is a necessary part in the constitution of 
steel. It has also been found that iron, in forming 
steel, which contains silicon, sulphur, phosphorus, 
arsenic, and similar matter, does not need or absorb 
as much carbon as if the iron is free from such ad- 
mixtures. Carbon may be replaced in steel by other 
matter. 

It requires more than common sagacity and pene- 



APPENDIX. 207 

tration to perceive the difference between the nature 
of the alloys of iron in the annealed state, and in 
their hardened condition. To assume, however, that 
the iron in the one case is a mechanical, and in the 
other a chemical combination, caused merely by the 
manner and time of cooling, is something which we 
cannot believe in. 

The hardening and annealing of steel is a pheno- 
menon of great interest, and rich in information ; 
but it is not a singular phenomenon ; it is related to 
those of the same nature in other metals, though it 
differs in degree. 

We do not commonly say that brass or bronze, when 
hammered, change from a mechanical mixture to a 
chemical alloy, or vice versa. The same phenomenon 
is observed here as in tempering or hardening steel. 
Bronze or brass becomes hard in hammering, and is 
softened by annealing, just like steel. More analo- 
gous, however, than the above metals to steel, is 
glass ; this, when heated and thrown into cold water, 
becomes very brittle, but by annealing is made soft 
and tenacious. We do not think of ascribing this 
difference in the nature of glass, when cooled slowly 
or suddenly, to the alteration of its constituent 
parts to such an extent as to convert it from a me- 
chanical mixture into a chemical compound. One 



208 MANUFACTURE OF ST'EEL. 

of the essential conditions of transforming a mecha- 
nical mixture into a chemical combination is, that the 
atoms are liberated — that the mass is perfectly fluid, 
so that an interchange of atoms may be possible. 
In all cases, at least one of the constituent parts is 
to be fluid, or in a gaseous form, or a change from a 
mechanical to a chemical constitution is of course 
impossible. Now, if we admit that carbon in a gas- 
eous form may combine with iron chemically, if both 
in combination are suddenly cooled, we cannot admit 
that the same happens in glass ; for in glass there is 
no element which can possibly be in an elastic fluid, 
or in a limpid state. Furthermore, silex, silver, man- 
ganese, and other matter, show a similar relation to 
carbon as iron ; and we do not think that anybody 
would assume two states of combination between iron 
and silicon, and between iron and silver ; the alloy 
may be soft or hard. It requires also a strong ima- 
gination to believe that in hammering annealed steel, 
a change from a mechanical to a chemical formation 
is effected, and still steel is hardened quite as well 
by hammering as by refrigeration. There is no heat 
to make carbon volatile. 

Speculations like the foregoing may seem, at first 
sight, but a waste of time, and of no practical use ; 
such, however, is not the case. The theory or science 



APPENDIX. 209 

of any art is always, at first, based on hypothesis ; 
of the truth of which we can know nothing until it is 
demonstrated by experience. The nature of steel 
in its hardened and tempered state has not been, and 
cannot be, based upon positive facts ; we have to 
reason by analogy. The science of making steel, as 
well as the investigation of its nature, is therefore 
based, and will be always based, upon hypothesis. 
The nearer that hypothesis is to the true state of 
facts, the more perfect will be the science, and the 
greater will be the advantages derived from the sci- 
ence in the art of manufacturing steel. Thus far, 
science has been of very little assistance to this im- 
portant branch of industry ; the whole is based upon 
practice. Why is this so ? There is scarcely any 
art at the present time which is not indebted to the 
researches and investigations of our scientific men. 
We believe that the whole science of steel-making is 
based upon a false foundation — upon an incorrect 
hypothesis. 

In this country, steel-making is in its infancy ; it 
has in no way advanced so fast as the manufacture 
of iron. We have no ore which is almost native 
steel, like the Germans ; nor can we expend as much 
labour in making iron as is done in Sweden. Our 
social relations do not admit of it, and nature has not 
18* 



210 MANUFACTURE OF STEEL. 

favoured us with similar conditions. Still, we have 
an abundance of good iron-ore, and a supply of fuel 
unparalleled in the known world. We have hands 
who are willing to work, and heads which are able to 
plan: why can we not make steel? We make at 
present nearly eight thousand tons per annum ; but 
that is little in comparison with what is consumed, or 
would be consumed, if it could be furnished at rea- 
sonable prices. All the steel we now make is used 
for springs, coarse saw-blades, and files. 

The manufacture of steel is necessarily involved 
in great mystery. All practical manufacturers are 
agreed that good iron is all that is required to make 
good steel. The art is simple and infallible, if the 
proper ore or iron is at hand. The ore from which 
the Germans make their steel is the crystalline car- 
bonate, or sparry ore, which they possess in great 
purity. The making of steel from such ore is very 
simple, more so than the making of iron from the 
same ore. But we cannot make steel in the German 
fashion, as we have no such ore, nor any suitable for 
the purpose. There is sparry ore in Vermont, North 
Carolina, Missouri, and perhaps in other States ; but 
it is not adapted to the manufacture of good steel. 
Even if we had ore like the German, we should find 
that their process is not suited to our country. 



APPENDIX. 211 

The wrought-iron made from the German steel- 
ore is very fibrous, tenacious, and of great cohesion. 
The Swedish iron of which English steel is made, 
is tender, very soft, and has no strength ; it is al- 
most cold-short. There is therefore a great differ- 
ence in the constitution. In the first case, German 
iron is the result of decomposed steel; the crude 
steel, or a part of it, in the operation of refining, 
has been converted into iron. In the latter case, 
this soft, tender Swedish iron is converted into steel ; 
and the softer the iron has been, the harder and 
more tenacious is the steel, provided the same labour 
is devoted to it. It is a fact that coke-iron will not 
make good steel, if treated in the best manner. 
Hot-blast destroys the quality of iron for steel, or, 
if not entirely, greatly injures it, even in the best 
kinds of charcoal-iron. Spring-steel may indeed be 
made of hot-blast and impure charcoal-iron ; but it 
will not have much strength, nor will it receive a fine 
edge. Experience has shown that hot-blast iron, of 
the same ore and from the same furnace, is much 
inferior to cold-blast ; so much, that nobody would 
think of using it for the purpose of making steel- 
iron. In Germany, every attempt to use hot-blast 
iron in the manufacture of steel has been attended 
with ill-success. 



212 MANUFACTURE OF STEEL. 

With these facts before us, we think it not difficult 
to form a reasonable hypothesis on the nature of 
steel ; and this hypothesis will furnish a basis upon 
which the art of making steel may be established 
more successfully than by the old theory. 

Pure iron is very soft, malleable, infusible, and 
cannot be welded. The admixture of any other mat- 
ter makes it stronger, harder, and fusible ; and a 
limited admixture imparts to it the quality of weld- 
ing. Iron follows the same law as any other metal, 
and is subject to similar alterations of its nature by 
foreign admixtures. There is no essential difference 
between iron, and other metals and their combina- 
tions, as a class ; but there is a difference in the phe- 
nomena in degree. This is a general law of che- 
mistry, and no peculiarity of the metals. All alloys 
of metals, as we have said, are harder than the mean 
hardness of their elements ; and the same is the case 
with iron. We may say that carbon, or phosphorus, 
is not a metal. This does not alter the case, how- 
ever ; for phosphorus and carbon impart to iron the 
same quality as silver, arsenic, chromium, or copper ; 
all these make iron hard, and so does silicon. The 
only difference is in degree. One-fourth of one per 
cent, of phosphorus or silicon makes iron more brittle 
than five per cent, of carbon, or ten per cent, of cop- 



APPENDIX. 213 

per. All alloys of iron, without exception, are brit- 
tle, when combined with it in its pure state, even if 
they make steel tenacious, as do platinum and its 
kindred metals. Silicon and phosphorus impart to 
iron the highest degree of brittleness, and also of 
hardness ; silicon appearing to assume the first rank. 
Hardness and tenacity are always combined where a 
perfect and intimate chemical combination has been 
formed; this is a law throughout art and nature. 
Imperfect relations, or impure crystals, are never 
tenacious, never hard; where uncombined particles 
occur between the legitimate atoms of matter, every 
quality resulting from a perfect chemical compound 
is impaired. A mechanical admixture of water in 
any crystal impairs its lustre, its hardness, and its 
cohesion. 

Silicon and phosphorus appear to be related to 
iron, as zinc is to copper. The strongest heat can- 
not disengage all the zinc in combination with cop- 
per ; the latter will always retain sixteen per cent, 
of the former. By chemical means, however, we 
may separate them perfectly. The same is the case 
with iron and silicon, iron and phosphorus, sulphur, 
and almost any other matter in combination with 
iron. Heat alone never can remove sulphur or phos- 
phorus entirely from iron ; for, before all the sulphur, 



214 MANUFACTURE OF STEEL. 

which is known to be very volatile, is expelled, 
the iron crystallizes for want of sulphur, and a por- 
tion of the latter is enclosed in the small atomic 
crystals, and cannot be removed until the crystal is 
re-opened. The same phenomenon happens with any 
salt dissolved in water, or in its mother-ley. Silicon 
is not volatile, and for that reason less inclined to leave 
iron than any other matter ; it may easily be seen why 
it is so difficult to separate silicon from iron. And 
as silicon makes iron very hard and very brittle, it is 
so much the more necessary to remove it, at least as 
much as possible, before we can expect to have iron 
fit for making steel. We must be careful not to con- 
found silicon and silex ; for iron may contain twenty 
per cent, of silex, and be perfectly malleable, soft, 
and strong ; still, it would not make steel. 

Throughout nature a law prevails that all matter 
of one kind is combined in certain definite propor- 
tions with other matter of a different kind, to form a 
third matter of still another kind. If two or more 
kinds of matter are not combined in exactly given 
proportions, the new matter formed from the combi- 
nation is imperfect. Such imperfect matter does not 
show that beauty, that finish in all its parts, which it 
would possess if the elementary or combining atoms 
were in exact relation to their affinities. Such an 



APPENDIX. 215 

imperfect creation is impure, is abnormal. If such 
a law pervades all nature, as it certainly does in 
every instance, why should iron and its relative mat- 
ter make an exception? We cannot think of any 
exception to the rule ; indeed, it is impossible that 
there should be any. 

In the case before us, it is difficult to produce a 
legitimate combination of iron with other matter. 
We shall endeavour to show the cause of this diffi- 
culty, and the necessity of removing it. 

Silicon is the most tenacious adherent of iron — 
its best friend ; but its influence is so great in mak- 
ing the iron hard and obstinate, that the greater part 
of it must be removed if we want the iron for steel ; 
indeed, we may say all which it is practicable to 
remove. The finest steel shows but one-eighth of 
one per cent, of silicon, and often less than that. 
Carbon, sulphur and phosphorus form volatile com- 
pounds with the oxygen of the atmosphere; these 
compounds do not re-combine with iron, and are very 
easily expelled. Silex, the oxidized silicon, is not 
volatile; nor is silicon itself; both remain, therefore, 
with the iron, in either one or the other form. All 
other matter increases the fusibility of iron ; and so 
does silicon ; but almost all other matter, with the 



216 MANUFACTURE OF STEEL. 

exception of a few metals, such as copper or silver, 
may be driven off by heat, or oxidized and evapo- 
rated. Silicon remains last of all ; and its admix- 
ture will have the effect of keeping the atoms of iron 
separate, or keeping the metal in a fluid state, until 
the silicon is oxidized and removed. The great co- 
hesive power of the iron particles will congeal the 
fluid iron compound before all the silicon or silex can 
be removed. It may therefore be asserted that no 
iron, no matter how it is manufactured, is entirely 
free from silicon or silex ; because most of the iron-ore 
contains silex, the walls of the furnaces contain silex, 
all fuel contains it, and fluxes and slag are not free 
from it. Silicon makes iron hard — silex does not; 
iron may be strong and tenacious, and contain much 
silex ; but it would not answer for the better qualities 
of steel. Silex can be in wrought and cast-iron, but 
not in steel, and much less in hardened steel ; for it 
will inevitably be converted into silicon by the car- 
bon of the steel. We must not conclude, therefore, 
that soft, fine, strong bar-iron is any more fit for 
conversion into steel than even cold-short, worthless 
iron. The qualification of iron for steel cannot be 
correctly judged of from its appearance; it can only 
be ascertained by actual trial, and careful chemical 
analysis. 



APPENDIX. 217 

Experience shows that the best steel contains the 
largest number of components, the greatest variety 
of matter. Silicon, sulphur, phosphorus and arsenic 
are as necessary elements in the constitution of steel 
as is carbon. Good steel may be made by simply 
adding carbon to wrought-iron ; but then the quality 
of the steel will depend upon the chemical composition 
of the iron used. We lay it down as a principle, that 
the combination of iron with other matter to form 
steel is to be a true compound of multiples ; and we 
assert further that the best steel is the result of such 
a combination, and the greatest number of the com- 
pound elements. The latter part of the above de- 
claration has been proved by experience ; the first 
part is a true deduction from the works of the Crea- 
tor. There is no finished form in the whole range 
of the creation but is the result of multiples of equal 
space, filled with matter of various kinds. 

In converting iron into steel, we have to combine 
it with such quantities of other matter as to form of 
one or more atoms of iron, one atom of steel. Steel 
is a new metal ; it is neither iron, glass, carbon, nor 
anything but steel ; it is distinct from iron and all 
its composing elements. Just as salt is distinct from 
muriatic acid, and distinct from soda, so steel is 
distinct from iron, or carbon, or sulphur, or silicon, 
19 



218 MANUFACTURE OF STEEL. 

or any other element. If ninety-nine parts of pure 
iron and one part of carbon form steel — we make 
use here of the true parts, instead of the equivalents, 
to be more explicit to those who are not versed in 
chemistry — ninety-eight parts of iron and two parts 
of carbon make better steel than the first; and 
ninety-seven parts of iron and three of carbon make 
cast-iron ; we are compelled to keep within the limits 
of two per cent, of carbon, if we want to form steel. 
If 98 parts of iron, 1 of carbon, and 1 of silicon, 
form brittle, hard cast-iron ; 98 parts iron, 1J car- 
bon, and J silicon, form steel ; but 98 parts iron, 
1| carbon, and | silicon, form better steel. We have 
to keep within the limit of J and J silicon, if we want 
steel at all. If 98 parts iron, 1 carbon, J silicon 
and | sulphur, make rather brittle steel ; 98 parts 
iron, 1J carbon, J silicon and f sulphur, make a bet- 
ter article — it would be unwise to put more sul- 
phur in. The same rule which guides our labours in 
these instances, is to be applied in all cases. Every 
addition of a new element requires an alteration in 
the quantity of the other components. 

The various elements do not combine in equal 
weights with iron, nor in equal weights among them- 
selves, to form the most perfect compound. We 
have no experience to guide us in determining the 



APPENDIX. 219 

relative quantities of the various elements in steel ; 
but science induces the conclusion that the elements 
in steel must be combined in the simple or compound 
ratios of their atomic weights. Good steel must ne- 
cessarily consist of one or more atoms of iron, one 
or more atoms of carbon, silicon, phosphorus, and the 
other elements. The atomic weight of iron is 339.2, 
of carbon 76.4, of arsenic 470, of azote 88.5, of cop- 
per 395.6, manganese 345.0, phosphorus 196.1, sili- 
con 277.4, and sulphur 201.1. All these elements, 
and still more, have been found in steel. They can- 
not combine in single atoms ; that is impossible ; 
there must be a starting point somewhere. If we 
commence with silicon, and argue that 1 atom of it 
combined with 25 atoms of carbon, the ratio of 
J to If parts, then it will require 322 atoms of iron 
to make 98 parts of iron. If such are the combin- 
ing numbers of these elements to form good steel, it 
is evident that, if there are more than 322 atoms of 
iron in the composition, the product will be a mix- 
ture of hard steel and soft iron, which of course will 
not make a reliable edge. If there are more than 
25 atoms of carbon, or 1 and a fraction of silicon, 
the same thing will happen ; for neither of them has 
any combination in steel. If there is more than 1 atom 
of silicon in 322 atoms of iron which is to be con- 



220 MANUFACTURE E STEEL. 

verted into blistered steel, we can well manage to put 
25 atoms or If per cent, of carbon into it. But if 25 
atoms of carbon and 1 atom of silex form the best 
ratio of alloy with iron to make steel, it is evident 
that, if there are 2 atoms of silicon to 25 of carbon, 
the compound is not good. If, in this instance, we 
alloy so much carbon with the iron as to produce 25 
atoms of carbon to 1 of silicon, the iron will be con- 
verted into good cast-iron. Here we are impelled to 
the conclusion that similar conditions prevail between 
all the elements of steel. 

We have it in our power to put as much other mat- 
ter into iron as we please, if the iron is pure ; but 
it is not in our power to combine it with a limited 
quantity of silicon ; neither is it possible to remove 
all the silex from the iron, in the practical operations 
attending its manufacture. As the amount of silicon 
is to be very limited in steel, and as it cannot be re- 
moved from bar-iron or steel, it follows that its 
removal is to be accomplished before the iron is put 
into shape for conversion. 

From the foregoing investigations, we are led to 
conclude that steel is a definite compound of iron 
and other matter, and that silex is the chief obstacle 
to the formation of such a compound. All our ener- 



APPENDIX. 221 

gies are therefore to be directed against silicon, or 
silex; because, if there is too much in the iron, it 
will degrade the steel. There never can be too little 
silex in iron to make good steel of it. 

How far practice confirms this theory, we will en- 
deavour to show. The East Indians, in making their 
iron for wootz, pound the ore very fine, and free it 
by washing, as far as possible, from all impurities. 
They then melt it in a small furnace, in a very short 
time, without lime or other fluxes, and obtain but 
one-fifth of the iron which the ore contains. The 
remaining four-fifths are converted into slag, which 
absorbs as much silex as its constitution will admit 
of; though that cannot be much, as the ore is pure, 
and the cinder has therefore to absorb its silex from 
the charcoal and the in-wall of the furnace. We see 
here how much care is taken to remove the silex at 
first, and the immense loss of iron that results from 
its removal. 

In making natural steel in Germany, the same 
principles are carried out, though not to so great an 
extent. The steel-ore of that country is naturally 
pure ; but it is still cautiously selected with respect 
to the making of steel. The blast-furnaces where 
these ores are smelted are well supplied with charcoal, 
and in most cases work without flux. Limestone, as 
19* 



222 MANUFACTURE OF STEEL. 

a flux, is avoided as much as possible. Most of the ores 
contain a large amount of manganese, which fluxes the 
silex, and is in all cases the most efficient flux. It is 
a generally diffused error that manganese is essen- 
tially necessary to manufacture good steel ; there is 
no magnesium found in any steel ; it serves in every 
instance to absorb the silex. 

The crude iron of the Germans, which is highly 
purified, and contains hardly anything but iron, car- 
bon and silicon, loses in the first operation in the 
forge, where it is converted into crude steel, twenty- 
five per cent., and in each subsequent refining heat 
from six to eight per cent. ; so that, on an average, 
not more than fifty per cent, of partly iron and partly 
steel are obtained. Probably not more than twenty- 
five per cent, of good steel could be obtained from 
the crude iron. 

The process by which Swedish bar-iron is "made, is 
that which is in general use in this country, and has 
already been described. The difference in quality is 
chiefly caused by crude iron and labour. Common 
Swedish bar is not particularly good ; we have, if not 
superior, at least equal qualities of charcoal-iron, 
even for steel-works. The Swedish and Russian iron 
of which common shear-steel is made, is, however, 
more uniform and pure than ours — the consequence 



APPENDIX. 223 

of more labour and material spent in making it. 
The best Swedish iron, that of which the finest Eng- 
lish steel is made, is not refined in what is called the 
German forge, but by a different process. The forge- 
fire is not lined with iron, or only on two sides ; very 
little iron is melted in at one heat ; no slag, scales 
or ore are used for boiling ; and the whole process 
goes on with great slowness and regularity. Much 
coal is used, much iron wasted, and a great deal of 
labour spent in the operation. The iron is very supe- 
rior, however, and is made nowhere but in the uplands 
of Sweden, near the ore-mines of Danemora. 

The burning of steel, or the converting process, is 
as well conducted in this country as in any other ; 
and there is also no difficulty in melting blistered 
steel, as well as tilting shear-steel. All we want is 
pure iron, and then there is no doubt that we shall be 
able to compete with the world in making steel. 

It is out of the question to imitate Sweden, Rus- 
sia, Germany, or any other country, in making iron 
. or steel. We should cultivate our own means, with- 
out reference to their method, and succeed in our own 
way. We need not copy the processes of other na- 
tions, no matter how highly cultivated those processes 
may be. Ours are peculiar conditions, and in no way 
resemble those of any other people. 



224 MANUFACTURE OF STEEL. 

The only practicable way of making steel in this 
country is, first to make blistered, and then cast- 
steel, as is now done. But we want a better article 
than is made at the present time, and for this pur- 
pose we want better iron. There ought to be no dif- 
ficulty on this score ; for we have extremely cheap 
ore, and, in spending two tons of ore where now but 
one is used for the same amount of iron, and even 
more than that, there ought to be no difficulty in ob- 
taining any quality of iron we desire. The magnetic 
ores at Lake Champlain are not surpassed in purity 
by any ore in the world ; indeed, they are almost 
pure iron ; but they are at present of little value. 
There is no reason why, from this ore, we cannot 
make iron equal to the best Swedish, and we could 
certainly make it more cheaply than we can import 
the common Swedish bar. Why do not the immense 
ore-beds in Essex county, New York, make good 
steel-iron ? It certainly is not the fault of the ore ; 
for that is of a very superior quality; nor can it 
arise from any scarcity of timber — that also is found 
in the greatest abundance. New Jersey possesses 
large deposites of material, and has every facility for 
making good steel-iron ; yet her great advantages 
are not improved. 

That Missouri and Wisconsin are not already in 



APPENDIX. 225 

the market with the best iron in the United States, 
may be excused on the ground of the infancy of the 
iron business in those States. There is no doubt that 
they could relieve us from the contribution we at pre- 
sent pay to Europe for good iron ; and we look for- 
ward with confidence to the period when our wants 
shall be supplied from those States. 

Pennsylvania is the only State where steel is made 
to any extent ; and seven-eighths of the whole amount 
manufactured in the United States is made by her. 
This is a little remarkable, as Pennsylvania is not 
favoured by nature for this quality. That State is 
hardly to be excelled in good merchant bar and 
foundry metal; but her hydrates, pipe-ores, and 
argillaceous iron-stones, are not at all qualified for 
making steel, or at least not good steel. The evil 
of our not being supplied with the best kind of steel- 
rods, is chiefly owing to the desire of reducing ex- 
penses in manufacturing. The finest iron-ores are 
wasted to make blooms worth thirty-five dollars per 
ton; while the judicious expenditure of but a few 
dollars more would convert the same ore into an iron 
equal to the common Swedish or Russian bar. 

We are forced to the conclusion, from all we have 
observed, that the making of good iron is not gene- 
rally understood, and that its importance is vastly 



226 MANUFACTURE OF STEEL. 

under-rated. We consequently suffer under a heavy 
tax to Europe for steel which we might readily make 
ourselves, and which we shall have some hope of 
making, as soon as our manufacturers relinquish the 
vain attempt to make cast-steel of puddled iron, and 
natural steel of anthracite or hot-blast iron. 



THE END. 



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